Pima County is among the most rapidly growing counties between 2007 and 2011, based on data given by the U.S. Census, which gives a county-by-county breakdown of where Americans moved from in that time period.

In the five-year span, net migration into the county was 9,467, with 52,077 people moving in and 42,610 leaving.

A large part of Pima's growth and atrophy came from within the state, with 18,250 Arizonans moving to the area, while 14,373 left the county for other parts of the state.

Maricopa County was the top destination for emigration and immigration. The report said 9,700 people came to Pima from Maricopa, while 5,867 left to move there.

Those who left Pima County, and went to another state, mostly moved to the counties around San Diego and Los Angeles, Calif. and Las Vegas, NV.

Many new Pima residents also came from those areas.