By contrast, in the Dallas-Fort Worth area, 18 percent of economic activity was in real estate and construction at the peak of the housing bubble. In Charlotte, N.C., it was just 15 percent.

Those cities have suffered during the recession, but not as much as the former boomtowns. Home prices in Charlotte are down only 11 percent from their peak, compared with 54 percent in Phoenix. And Charlotte’s job losses, while severe, are also spread almost evenly across several sectors. That is unlike Phoenix and Las Vegas, where job losses in construction have far outstripped those in other industries  down by 45 percent from their peak in Phoenix, for instance.

In Arizona, the construction job losses helped drive the unemployment rate to 9.2 percent this July, up from 3.7 percent the same month two years ago. Florida and Nevada, with unemployment at 10.7 percent and 12.5 percent respectively, are also struggling with high rates of joblessness.

While central Arizona has other economic pillars, including a substantial technology and aerospace industry, some experts say only a revival in residential construction can provide enough employment to return the region to strong growth.

“I really think we have to start building houses again to get the economy rolling,” said Marshall Vest, a University of Arizona economist who has written closely watched economic forecasts of the state for more than 30 years.

A strong housing recovery faces serious obstacles in all the former Sun Belt hot spots, however. Among them is the prospect that the population growth to which they have long been accustomed is stagnating, or even beginning to reverse.

Florida’s population shrank recently, for the first time since 1946. According to estimates by the University of Florida’s Bureau of Economic and Business Research, the state lost more than 58,000 residents in the year leading up to April 2009.