There were 11 co-op sales at more than $20 million last year, up from four in 2005, the report said.

Because co-op sales are not public records, there are no statistics that describe how prices have changed over the years.

And while co-op sales posted the biggest increase in the first quarter, prices continued to drop.

The brokerage said it analyzed 2,463 co-op sales completed in 1989 and estimated that the average selling price per room, $108,040, had declined 9.2 percent.

Real estate brokers who track co-op sales identified 11 other apartments that had been sold in the building since August 2003.

But even though there were some co-op sales at Newmark's building in mid-1929, construction stopped in the summer of 1930.

Nevertheless, only four of the co-op sales were over $10 million, including one for $13 million.

It's expected that total co-op sales for the year could reach 700, compared to 568 in 1993.

Countering the overall trend, the 1,797 co-op sales were a record and were 8 percent more than in 1999.

IN the same period, co-op sales have increased.