Purchases were revised down to 4.19 million for 2010, down 15 percent from a prior estimate of 4.91 million, the real estate agents’ group said in Washington. There was a comparable downward revision to inventory, and median prices were little changed from prior estimates.

Sales climbed 4 percent in November to a 4.42 million annual pace, from a revised 4.25 million rate the prior month that reflected the benchmark revisions.

“Since 2007, things began to diverge” with other housing data, Lawrence Yun, the group’s chief economist, said in a news conference today as the figures were released. “Nothing in the local markets changed, it was an aggregation problem.”