WASHINGTON, DC—Amid a disappointing report from the National Association of Realtors on last month's existing-home sales, there's a nugget of good news. Sales of existing apartment units—including condominiums and cooperatives—held their own in April even as existing-home volume showed an overall decline of 3.3% from March, according to NAR data.

Condo and co-op resale volume was unchanged from March's seasonally adjusted level of 610,000 units, and was 3.4% higher than April 2014, when 590,000 units changed hands. The median price of a for-sale apartment was up 0.4% year-over-year to $206,100.

Overall, existing-home sale volume fell to 5.04 million units in April from an upwardly revised 5.21 million in March. Even so, sales have increased Y-O-Y for seven consecutive months and are still 6.1% above a year ago. Additionally, April marked two consecutive months of sales exceeding five million units.

“April's setback is the result of lagging supply relative to demand and the upward pressure it's putting on prices,” says Lawrence Yun, NAR's chief economist. NAR notes that although supply picked up from March, it's still down 0.9% Y-O-Y.

Yun adds, however, that “the overall data and feedback we're hearing from realtors continues to point to elevated levels of buying interest compared to a year ago. With low interest rates and job growth, more buyers will be encouraged to enter the market unless prices accelerate even higher in relation to incomes.”

April also saw existing homes sell faster (an average of 39 days) than at any time since July 2013 (42 days). It's also the second shortest time since NAR began tracking in May 2011.

“Housing inventory declined from last year and supply in many markets is very tight, which in turn is leading to bidding wars, faster price growth and properties selling at a quicker pace," says Yun. “To put it in perspective, roughly 40% of properties sold last month went at or above asking price,” the highest since NAR began tracking this metric on a monthly basis in December 2012. The Census Bureau is scheduled to release its monthly new-home sales report for April on May 26.