Crunching their own data and some others’, the folks at John Burns Real Estate Consulting found a ton of interesting information about what kind of housing choices 20-somethings are likely to make.

Let’s check out some of the things they found.

Going from renting to buying. First of all, the number of renters who moved out to buy a home rose in the last quarter of 2011, if only slightly. Back in 2007, about 17% of renters bought homes each quarter, but that number has been down around 11% per quarter since 2010.

First-time buyers declining. At one point, first-time buyers made up half the market. These days it’s less than a third. Quoth Burns: “While purchasing a home is simply out of the question for most young adults, many are still capable of renting on their own, and millions of others have reverted to shacking up with mom and dad.”

Living at home. The Pew Research Center found that 41% of 25 to 29 year olds currently live with their parents, along with 17% of 30 to 34 year olds. But get this: According to a imagerather large Burns survey, more than 70% of people are considering buying a larger home at some point to accommodate extended family, and another 19% are certain they will. The kicker? In most cases, “extended family” means adult children.

20-something homeowners. Burns projects renting to rise over the next several years (“[more than] 8 million renter households will be added from 2010 to 2015″) for several reasons. For 20-somethings, the big one will be debt and spending — from student loans to gadget purchases, they simply won’t have the income to qualify for a mortgage.

If you want more, including lots of charts, head on over to the John Burns site.