Office vacancies in the United States fell to 17.5 percent in the first three months of 2011, a slight decrease from 17.6 percent in the fourth quarter and the first decline in more than three years, Bloomberg reported.

Asking and effective rents also improved for the second consecutive quarter following more than two years of declines, according to New York-based property research firm Reis Inc.

“This is the first quarter, at least on a national basis, where the change is strong enough to qualify it as the first quarter of a recovery,” Ryan Severino, a Reis economist, told Bloomberg. “We have finally gotten to an inflection point where the good is starting to outweigh the bad.”

New York City and Washington, D.C, have led the rebound, Reis said, which is now spreading into other metropolitan areas.

Arthur Jones, a senior economist with CBRE Econometric Advisors in Boston, said he was cautiously optimistic that the market is entering a recovery and noted that San Francisco, Pittsburgh, Dallas and Austin, Texas, are among the cities most likely to have rent gains next year.

“We need to see another quarter’s worth of data before we’d say the market’s swung into recovery,” he said.

Similar to Reis’ findings, preliminary figures from CBRE show that the U.S. office vacancy rate fell to 16.5 percent in the first quarter from 16.8 percent a year earlier.