Just 33% of primary residences sold this year were purchased by first-time buyers, down from 38% last year to the lowest level since 1987, the National Association of Realtors reported Monday. The NAR says that the first-time-buyer share of home sales has typically hovered around 40% since 1981. The headwinds facing young buyers are well known: higher student debt, rising rents and a weaker job market have made it harder for would-be buyers to save for a down payment and qualify for a mortgage, particularly in a lending environment where banks are much less willing to overlook credit blemishes or spotty incomes. Separate surveys, including one by the New York Fed earlier this year, showed that insufficient savings or incomes were the biggest headwinds keeping renters from buying homes. Many households may also be less able to get help from their parents than in the past, because their parents’ homes have fallen sharply in value. Advocates of looser lending standards may point to the NAR’s latest survey to highlight problems on the mortgage market. But it’s worth noting that the share of first-time buyers didn’t increase during the housing bubble, when it was too easy to get a mortgage. That’s because home prices were rising. The share of first-time buyers fell to 36% in 2006, at the peak of the bubble, from 40% in the prior three years. And even though credit was much tighter in 2009 and 2010, the share of first time buyers jumped to 47% and 50%, respectively. Lower home prices helped. So, too, did an $8,000 federal tax credit for first-time buyers, which expired in June 2010. Home prices have been rising for the last two years—and first-time buyers have accounted for a falling share of sales in that time. Rising prices have fixed a number of ills ailing the housing market. They make consumers more willing to purchase homes or fix up the ones they live in. They make it easier for owners to sell if they get into trouble on their mortgage, limiting foreclosures. But rising prices also make homes less affordable, especially for the marginal buyer, which in many cases is also the first-time buyer. Rising home prices can be a two-edged sword. Also, even though it’s been possible throughout the housing downturn to get a mortgage with a down payment of just 3.5% through the Federal Housing Administration, the FHA has raised the fees that it charges buyers significantly over the past few years, making those loans more expensive. The NAR survey also found that people are staying in their homes longer than in the past. The median age of tenure–that is, the amount of time a typical homeowner stays in one house–rose to 10 years in the most recent survey, from six years in 2007. The typical first-time buyer last year was 31 years old, while the typical repeat buyer was 53. The NAR conducts an annual survey of buyers and sellers by mail. It received 6,572 questionnaires back that it had sent to 72,206 home buyers. It covers the 12-month period ended in June.