Daniel Baum, the group's COO, told The Observer what most suprised him in the 2007 data was Chelsea's resiliency. "A good percentage of property stayed positive at a time when a big amount of inventory in the condo market was coming on line," he said.

Average rents for doorman studios went up 15 percent year-over-year, finishing 2007 at $2,627. Non-doorman studio rents were down 1.7 percent year-over-year, finishing at $2,131 in 2007.

Rents for one-bedrooms in non-doorman buildings increased by 19.2 percent last year, the most of any Chelsea category, to $2,981, while one-bedroom rents in doorman buildings increased by just 2 percent to $3,947.

Non-doorman studio rents fared less well last year, dropping by 1.7 percent from 2006 to $2,214.

Meanwhile, two-bedroom rents in doorman buildings plunged to $4,785 last year, a 22 percent drop from 2006. The average rent for a two-bedroom in a doorman building dipped by 2.7 percent last year, to $6,260.