NEW YORK (CNNMoney.com) -- Flagler County, Fla., was the fastest-growing housing market in the United States last year, according to a U.S. Census report released Monday.

The market's housing stock expanded by 14.8 percent, or 5,000 units, in the 12 months ended July 1, 2005, the most recent data available.

There were 124.5 million housing units in the entire United States, a 1.5 percent increase from a year earlier.

Three of the top four fastest-growing counties were in Florida, with Sumter County - 12.8 percent growth - at No. 2.

Pinal County, Arizona, was third with a 10.2 percent increase, but another Arizona county, Maricopa, recorded the largest numerical increase of any U.S. county; it added 52,000 homes during the 12 months, a 3.7 increase.

Nevada added homes at a faster pace than any other state; its growth rate of 4.4 percent was three times the rate of the nation as a whole. Florida was the numerical leader with 246,842.

Rhode Island added just 1,505 homes, a 0.3 percent increase, the lowest rate in the nation. Washington, D.C., which added 1,175, was the lowest in terms of sheer numbers, but its rate of growth was 0.4 percent, just nosing out "Little Rhody."

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