Sales of condominiums and townhomes in San Diego County dipped in February, and were down sharply year over year, as a supply shortage continued to put a damper on the area’s housing market.

The Greater San Diego Association of Realtors reported the number of attached homes sold last month slid 1 percent to 687, while closings of single-family, detached units increased by a slightly greater share, to 1,428.

Looking at median sale prices, both types of homes posted a 1 percent increase from January, with condos and townhomes rising to $380,000, and single-family homes hitting $557,500.

The group’s president, Bob Kevane, said the market is being driven by a lack of homes for sale.

“The low-inventory situation and affordability crunch has been particularly hard for first-time homebuyers,” he said in a news release.

Year-over-year comparisons tell a somewhat unexpected story: While the single-family sales volume was off by less than 1 percent from February 2016’s total, condo and townhome sales fell more than 14 percent from a year earlier.

More predictable was that median prices were up in both cases from 12 months before — 8 percent for single-family homes, 10 percent for condos and townhomes.

It may be too early to call the disproportionate slowdown in condo sales a trend, but it does appear to clash with the pattern of recent years.

In 2016, the increase in sales of attached-home outpaced that of single-family homes by a margin of 3.1 percent to 0.3 percent, SDAR reported. The year before, the county’s condo sales volume was up 9.8 percent — 3 points greater than the increase in detached homes, SDAR reported.

San Diego Realtor Dan Becker said the expectation continues to be that condos will sell more briskly than they have in the past, simply because first-time buyers have a hard time coming up with the money for a detached home.

“Again, it’s a matter of inventory,” he said.