Thirteen percent of first-time homebuyers surveyed by the National Association of Realtors last year said their primary reason for purchasing — primary reason, mind you — was the $8,000 federal tax credit.

That was the second most popular answer after “I wanted to own my own home.” The third most popular answer: “Affordability of homes,” which was the top pick for 8 percent of first-time buyers surveyed.

The trade group’s survey results have been out for a while — and the questionnaire itself was mailed out last July to buyers who purchased between July 2009 and June 2010 — but, hey, I just stumbled across it. I thought you might like to chew over the figures, too. Is it alarming that anyone took on the responsibility of homeownership primarily for an $8,000 tax break … or, considering the multi-billion-dollar cost of that incentive, that just 13 percent did?

For repeat buyers, the tax credit was $6,500, but only assuming they met the very specific qualifications. It wasn’t nearly as popular as the credit for first-time buyers, and the survey results reflect that: Just 3 percent of repeat buyers cited the credit as the primary factor for their purchase. Desire for a larger place was the key motivator.

If you bought — or sold — in the last few years, share: What was your primary reason?  What about the secondary and tertiary ones?