Sales of condominiums and cooperative apartments across the United States set a record in the second quarter, jumping 6.6 percent, the National Association of Realtors reported.

Condo sales have risen steadily during most of the past decade, driven by first-time buyers and by baby boomers downsizing as kids leave home.

In 1993, condo and co-op sales accounted for 9.6 percent of all existing-home sales.

Last year, "The demand for housing from growing and aging population segments, and improvements in the economy, are bigger factors in record condo sales," said Walt McDonald, who is president of the NAR.

Popularity is taking a toll on affordability. The median existing condo/co-op price during the second quarter was $189,400, up 12.1 percent from the same quarter in 2003.

The median price of an existing single-family home was $183,800 in the second quarter, up 9.1 percent from 2003.

A higher concentration of condos in more expensive housing markets was part of the reason for the price differences. But outside of resort and popular second-home destinations, condos typically cost less than houses.

In the South, existing condo and co-op sales rose 4.4 percent in the second quarter to a record 454,000 units and were 16.1 percent above the same quarter in 2003. The median price in the South was $163,300, or 24.6 percent higher than a year ago.

In the Northeast, such sales jumped 13.8 percent in the second quarter to a record 173,000 units. The median price was about $211,100, up 10.1 percent from a year earlier.

In the West, resale activity rose 6.8 percent to a record annual rate of 253,000 units, or 10.5 percent above the sales rate during the second quarter in 2003.

The median condo price in the West was $226,200 in the second quarter, up 8.6 percent from a year ago.

Resale activity in the Midwest increased 5.5 percent, with a record 116,000 units in the second quarter and was 13.7 percent above a year earlier.

The median condo price in the Midwest was $178,300, up 6.4 percent from the second quarter of 2003.

The NAR data does not break out condo and co-op sales separately.