SPOKANE, Wash. (AP) - The Tri-Cities and Olympia had the highest percentage of growth among the state's metropolitan areas between 2007 and 2008 and also since the 2000 Census, according to estimates released Wednesday by the U.S. Census Bureau.

Seattle-Tacoma-Bellevue, the state's largest metro area, added the most residents in both time periods.

Washington state grew 1.5 percent between July 1, 2007 and July 1, 2008, to 6.549 million residents, exceeding the nationwide growth rate of 0.9 percent, according to the Population Reference Bureau.

Thousands of residents in the Tri-Cities of Richland, Kennewick and Pasco work in federally funded research and cleanup of the Hanford nuclear reservation. The region in southcentral Washington also has a large agriculture industry which has lured thousands of workers from Mexico, and rising numbers of retirees are drawn by the hot, dry summer weather.

Between 2007 and 2008 the Tri-Cities added 7,936 people, a growth rate of 3.5 percent, for an estimated total of 235,841 residents. That lifted the Tri-Cities past Yakima, 234,564, into sixth place among the state's metro areas.

Olympia, the state capital, grew up 2.9 percent, adding 7,015 people for a total of 245,181.

The Seattle area grew by 1.4 percent in the past year and added the most people, 46,588, to reach a population of 3.344 million, 15th among the nation's largest metro areas.

Bellingham grew by 2.2 percent, Vancouver by 2 percent, Mount Vernon-Anacortes 1.8 percent; Spokane 1.5 percent, Wenatchee 1.4 percent, Yakima 1.1 percent, Longview 1 percent and Bremerton 0.7 percent.

Vancouver is in Clark County, part of the Portland, Ore., metro area. Clark County added 8,240 residents, a growth rate of 2 percent, to 424,733 people.

Metro areas generally include a central city and the population of the surrounding county or counties. The Seattle-Tacoma metro area covers King, Pierce and Snohomish counties, and the Tri-Cities metro area is Benton and Franklin counties.

From the 2000 Census to July 1, 2008, Vancouver grew 23 percent, tops in the state. The Tri-Cities grew 22.9 percent, Olympia 18.2 percent, Bellingham 17.8 percent, Mount Vernon-Anacortes 14.6 percent, Spokane 10 percent, the Seattle area 9.9 percent, Wenatchee 9 percent, Longview 8.9 percent, Yakima 5.4 percent and Bremerton 3.4 percent.

The state has grown 11 percent since 2000, adding 655,081 people.

Among so-called micropolitan areas, a smaller city and the surrounding county, Moses Lake was the fastest growing in Washington at 2.8 percent in the past year to a total of 84,697.

Nationally, the Census reported that the nation's economic crisis has resulted in fewer Americans moving to Sun Belt hot spots in Nevada, Arizona and Florida.

The latest population trends come as state and local governments are deciding where to pour billions of dollars in federal stimulus money to develop schools, roads, bridges and other infrastructure. The nation's decennial head count, used to apportion House seats and redraw congressional districts, also is fast approaching.

Despite slowing migration, the South and West continued to account for the most growth in the past year.

Raleigh-Cary, N.C., and Austin-Round Rock, Texas, were the nation's fastest-growing metro areas with growth rates of 4.3 percent and 3.8 percent, respectively.

The census estimates used local records of births and deaths, Internal Revenue Service records of people moving within the United States, and census statistics on immigrants.