According to a preliminary state report, Arizona's population surpassed that mark this summer. The latest estimates put the population at 5,045,275 for the state, and 2,991,250 for Maricopa County, the county that encompasses metropolitan Phoenix. Pima County, which includes Tucson, has reached a population of 866,125.

The state's population has grown 37% since 1990. The Phoenix metropolitan area has grown even faster, climbing 40.4% over the past decade--one of the fastest growth rates of any major metropolitan city in the nation.

The state's rural communities are growing even faster. The counties that include the cities of Kingman, Prescott and Casa Grande grew by 45% to 50% since 1990, the Department of Economic Security report says.