Ever wonder how much the folks who build, sell and finance houses earn? How much of what you paid went right to their bottom line?

If so, you've come to the right place. Now it can be told who makes what in the typical real estate transaction. Let's take a look, starting with the companies that build houses.

BUILDERS: According to the National Association of Home Builders' (NAHB) latest "cost of doing business" study, builders averaged just a tad over $3 million in gross profit in 2014 on $16.23 million in revenue. That's an 18.9 percent gain.

But after accounting for operating costs that averaged $2.02 million, their take was just 6.4 percent, or $1.04 million.

The remarkably detailed report goes further, though, breaking down the data by type of builder: those who build solely on their own lots, those who build on lots owned by their clients and those who do both. It also details earnings by region and by volume, and by builders who put up fewer than 25 houses a year and those who build more.

Since there is not enough space here to go into each category, let's just concentrate on the two largest segments: builders with land costs, also called speculative builders, who make up 38 percent of the total respondents to the NAHB survey; and combination builders, who build on their customers' lots as well as their own land, and make up 37 percent of respondents.

According to the survey, speculative builders' net profit averaged 5.9 percent. So if you paid $356,200 for your new house -- the average price for new homes in March, according to the latest figures from the Census Bureau -- figure that your builder pocketed $21,016 on your deal, give or take.

Combination builders netted more -- 7.6 percent per house, on average -- which works out to $27,071 in pure profit on the typical house. Not bad, except that it sometimes takes years to obtain the necessary government approvals to build, and then 90 days or so more to actually construct the place.

Breaking the profit picture down another way, small-volume builders, who comprised 65 percent of survey respondents, earned 5 percent on average, while their larger colleagues, aka production builders, made 6.8 percent.

REALTY AGENTS: The men and women who sell houses earn anywhere from under $10,000 annually to more than $250,000, depending on experience, hours worked and education. A deeper dive finds that the median yearly pay for a sales agent in 2014, according to that year's National Association of Realtors' annual member profile, was $23,300.

It is well understood that agents work on commission, typically 6 percent. But what is not so well understood is that they don't get all of that. Rather, they split their fee with their brokers, under whose licenses they work.

Nearly 80 percent of all agents work under a split-commission arrangement, generally 50-50. But the more productive they are, the better the split. And 13 percent keep the entire commission and pay their brokers a so-called "desk charge."

Income varies widely in the industry: After taxes and expenses, appraisers take home about $46,200, and brokers take in $96,200 if they don't act as agents themselves ($45,500 if they do). Experienced agents with 16 or more years on the job net a median of $42,000, but 3 percent walk away with more than a quarter-million dollars.

LENDERS: In 2015, independent mortgage lenders -- those unaffiliated with larger banks or with the mortgage subsidiaries of chartered banks -- earned an average of $1,189 in profit on each loan they originated, according to the Mortgage Bankers Association's (MBA) annual performance report. But in the first quarter of this year, their net gain on each loan slipped to $825.

A closer look shows that net production profits in 2015 were 55 basis points, or 0.55 percent of the loan amount. So multiply that times the amount you borrowed, and you'll have a good idea of what your lender made off of your deal, before expenses.

Because of larger loan balances last year -- $239,265 vs. $223,108 in 2014, a jump of 7 percent, and up 22 percent since the housing market collapsed in 2008 -- lenders' bottom lines rose nearly $450 per loan in 2015.

To show you how volatile the mortgage market has become, at least for lenders, the average pre-tax profit per loan in the first quarter dropped to 33 basis points, or 0.33 percent of the loan amount. Since the MBA began keeping records, net production income has averaged 52 basis points.

Houston lost its locally famous Bullock-City Federation Mansion in 2014 to a developer who plans to erect townhouses on the site.

The house may not have been worthy of a place on a list of historically significant structures. But the 5,000-square-foot structure that was erected in 1906 on a 30,000-square-foot lot was the first in the sweltering Texas city to have air conditioning. And its demise was mourned by more than a few people.

"It's a beautiful building," Ernesto Aguilar, general manager of KPFT Radio, which sits next door, told the Houston Chronicle at the time. "It is sad to see a piece of Houston history going the same way as many others do."

Teardowns -- in which builders or private individuals purchase an aging, outmoded house, then demolish it and replace it with a modern home that will suit today's homeowners -- are currently on a tear in Houston. Permits for teardowns are up by 22 percent in the city this year.

And that phenomenon isn't limited to Houston. Barry Sulphor, a real estate agent in the Los Angeles area, counts no less than 100 teardown sites in the so-called "beach cities" where he plies his trade: Hermosa Beach, Redonda Beach and Manhattan Beach. "And I'm sure there are just as many in Venice, Santa Monica and Beverly Hills," Sulphor says.

According to the National Association of Home Builders' (NAHB's) best count, nearly 8 percent of all single-family housing starts in 2015 were attributable to teardown-related construction. That's roughly 55,000 older houses gone forever, and that's on top of the 31,800 single-family teardown starts in 2014.

In some instances, the houses that are destroyed are outmoded, functionally obsolete relics that no longer serve a useful purpose. But in other cases, they work just fine and simply lack up-to-date amenities. And some have historical significance that may or may not be worthy of saving.

Usually, the places that replace a teardown are larger, covering more of the lot and rising higher than the old place -- often to the maximum height allowable under local zoning rules.

Sulphor recently sold two lots where the old houses were taken down. One was bought for $1.35 million by a builder who plans to put up a house with a nearly $4 million price tag. The other was purchased for $2.15 million by a retired couple who "love the creativity of working with architects to design luxury beach properties," according to Sulphor. "When the new place is completed, it will fetch close to $5 million."

Not everyone sees the benefit of teardowns. The leading opponent is the National Trust for Historic Preservation, which argues that they are an "epidemic" that is "wiping out historic neighborhoods one house at a time. As older homes are demolished and replaced with dramatically larger, out-of-scale new structures, the historic character of the existing neighborhood is changed forever."

Says Richard Moe, a former president of the National Trust: "From 19th-century Victorian to 1920s bungalows, the architecture of America's historic neighborhoods reflects the character of our communities. Teardowns radically change the fabric of a community. Without proper safeguards, historic neighborhoods will lose the identities that drew residents to put down roots in the first place."

But the NAHB, which admits that teardowns "have become a significant modus operandi" for its members in some parts of the country, counters that the new houses often "breathe new life into older communities."

Because teardowns are sometimes controversial, folks considering buying an older place with the idea of taking it down and putting up a new house should proceed cautiously. Often, these old homes are not advertised for sale on the open market or in the multiple listing service, so the challenge begins with finding out about one, says Sulphor. And once you do, the agent suggests making absolutely sure the condition of the current home is such that it cannot be salvaged.

Would-be buyers should also determine, before making an offer, whether what they plan to build conforms to local restrictions. Preservationists often use -- or try to change -- local building codes to push back against teardowns.

On the other hand, people trying to sell old properties that are teardown candidates should make sure whatever offers they receive are legit, Sulphor advises. Look for the proof that they have the funds to close the deal, especially if they say they will pay with cash and have no need of a mortgage.

Sellers should also realize that selling a property "as-is" does not insulate them from their obligation to disclose any issues that might impact value. The term "as-is" means only that the house is being offered and sold in its present condition.

When the limits on two of Bill Johnson's credit cards were lowered from $20,000 to $6,000, his outstanding balances jumped from a perfectly acceptable 20 percent to a dangerously high 66 percent.

It wasn't Johnson's fault that the card issuers lowered his limits. They were just following the requirements under the CARD Act of 2009, legislation designed to establish fair and transparent credit practices.

You might say he was the "beneficiary" of a law intended to help him -- as long as you kept your tongue planted firmly in your cheek.

Through no fault of his own, lenders now look at Johnson's credit file and see a would-be borrower who no longer qualifies for the lowest possible mortgage rate. Now he's in the subprime category, and to a lot of lenders these days, subprime borrowers are verboten.

Nearly a decade after the mortgage market meltdown -- which was caused, in part, by overzealous lending to unqualified homebuyers with less-than-pristine credit -- subprime borrowers remain forbidden fruit, fit only for government-backed loans, if that. For the most part, lenders who only offer conventional loans won't touch them.

Tim Ranney says that sometimes, lenders are smart not to do business with clients whose credit scores are below 650. But, he is quick to point out, many of those with scores below that magic number are acceptable credit risks, as long as they are properly underwritten.

And Ranney, who shared the hypothetical example of "Bill Johnson" above, should know. He is president of Clarity Services, one of the new batch of credit-reporting agencies that have cropped in recent years to challenge the supremacy of the three major credit repositories: Equifax, TransUnion and Experian. Or if not to challenge them directly, then at least to add to the documentation on which lenders base their decisions.

Clarity focuses on the "underbanked," near-prime and subprime consumer who have minimal credit records. It has useable credit information on 55 million people that are considered subprime. From a pure data standpoint, adding reports such as the one from Clarity will allow lenders to approve what otherwise would be marginally risky borrowers who previously would have been turned down.

The company also sponsors important research into what Ranney has relabeled the "nonprime" sector. The company backs numerous academic studies, but has no say-so in their findings. Its only requirement is that it is the first to publish the results, which are posted on its website, nonPrime101.com.

Whereas prime-rated borrowers fit into an easily categorized box, nonprime folks are "defined by what they're not," says Aaron Klein, policy director of the Initiatives on Business and Public Policy at the Brookings Institution. "Young people with limited credit experience, single parents with credit issues, college kids and abusive credit defaulters are all lumped into one."

But they're not all the same, according to Klein. He was the lead speaker at a recent nonPrime101 conference in Tampa, Florida, where the latest Clarity-sponsored research was presented. Whereas 1 in 6 nonprime borrowers is insolvent and stuck in a downward spiral, the rest are merely "illiquid" -- as Klein explains, "They are likely to pay back; they just don't have the cash right now."

The usual driving factor of illiquids, 60 percent of whom are hourly workers, is an unforseen income drought. If there is a major snowfall, for example, snowplow drivers make out like bandits. But the cleaning lady who normally works six days a week may not be able to get to her job sites for a few days, and will lose money. Ditto for waitresses and bartenders who can't get to restaurants and bars.

Or when a divorced dad loses his job and can't make his support payments, the kid's mom also feels the pinch. When it rains for a solid week, roofers can't work at all. When a holiday falls on a Friday, your paycheck may not arrive on Saturday in time for you to get to the bank.

These are real-world scenarios of otherwise good people who hit a bump in the road. And the challenge for lenders is how to identify them for what they are, as opposed to serial insolvents, who take larger and larger risks in an attempt to pull a rabbit out of a hat and postpone the eventual day of reckoning.

That's where the new breed of credit bureaus like Clarity, PRBC, VantageScore and others come in. They collect the data the majors don't -- things like rent and utilities, which are not reported to the big three credit repositories; monthly unsecured obligations like payday loans, family loans and car title loans, and information that validates that the person's stated income is consistent with what was said on previous loan applications.

"There should be a set of facts everyone can count on," says Ranney. "Even as you go down the credit spectrum, there is a healthy percentage of the population that, within the limits of their ability to repay, are good credit risks. If they take a loan they can afford, they will pay it back.

"Low income is not automatically nonprime, and high income is not automatically prime. There are a significant number of consumers with low credit scores who, for one reason or another, have experienced some kind of financial setback. But they are completely stable, and have enough income to handle a mortgage."