Nearly 3,000 fewer homes were listed for sale last year in Snohomish County than in 2010, according to a report released Monday by the Northwest Multiple Listing Service. But sales of single-family homes rose 9.6 percent, and the median single-family-home price in 2011 dropped 11.6 percent to $243,000.

The median price for single-family homes hasn’t been that low since 2003, when it was $230,950.

Over the past 12 months, the county has seen 15,281 single family homes and condos come on the market. That’s down from 18,137 new listings in 2010. The county finished 2011 with a housing supply of 3.2 months, meaning it would take that long to sell the houses on the market if no additional homes were listed. It averaged 3.69 months of supply.

Economists estimate that a supply of three to six months indicates a balanced market. The county’s supply of homes is the lowest in the state.

Last year, 9,316 homes and condos were sold in the county, with combined sales of $2.4 billion.

Sales of condos in the county increased 25.8 percent in 2011 compared to 2010 with 1,545 condos selling last year. Condo prices, however, dropped 22.9 percent from 2010. The median condo price in 2011 was $162,000.

Sales of high-end single-family homes, which the multiple listing service classifies as homes that sell for $1 million or more, were few. The county had 18 homes sell for more than $1 million in 2011. Thirty-seven condos sold for $500,000 or higher.

Single-family-home sales were the strongest in the Edmonds School District last year, with Everett School District a close second. Edmonds had 1,395 single-family-home sales, compared to 1,348 in Everett.

The median price for home sales in the Marysville School District came in at $185,000. About 867 homes sold there in 2011. Homes also sold well in the Snohomish County portion of the Northshore School District, where 707 homes closed last year. The median sales price was $346,100.