Chris Caskey, The Union Democrat

U.S. Census Bureau statistics released last week show small, rural cities continue to lag growth-wise as big cities grew, a sign of Americans' post-recession preference for urban living.

The trend is evident in this region, where the cities of Angels Camp, Sonora and Jackson saw their populations slip in the two years since 2010. The census estimates show Angels Camp's population dropped 3 percent, from 3,836 to 3,735, Sonora's was down 2 percent, from 4,903 to 4,804, and Jackson's dropped 1.7 percent, from 4,651 to 4,570.

In contrast, bigger cities in the region, like Modesto and Stockton, grew slightly - about 1 percent and 2 percent, respectively.

Nationwide, cities with booming regional economies continue to see the biggest gains. Seattle, San Francisco, Austin, Texas, Raleigh, N.C., and Washington, D.C., are among cities seeing an apartment-construction boom.

Farther-out suburbs - known as exurbs - saw their growth slip to 0.35 percent, the lowest in more than a decade.

Experts say the reasons likely combine economic and demographic factors. More rural communities have lost people seeking jobs in stronger economies as the 2008 recession continues in many places, while the older populations in many rural communities are not replaced.

"If you don't have positive migration you will have asmall decline," said Bill Spooling, a demographics researcher for the California Department of Finance.

Spooling said small, rural communities like those in the Mother Lode show more deaths than births. The region is already older on average than the Central Valley, Bay Area and Southern California, and the lack of new, young residents fuels the shrinkage, Spooling said.

"We see it in what I would consider to be mountain and recreation counties," he said.

Economists generally had played down the recent city boom as an aberration, predicting that young adults in the recovering economy would soon be back on the move after years of staying in big cities. But growth in 2012 indicates young people - as well as would-be retirees seeking quieter locales - are remaining longer in urban areas, where jobs are easier to find.

Prior to 2011, suburban growth had consistently outpaced big cities' since 1920.

"Cities have become more appealing to young people, with more things to do and places to see," said Mark Obrinsky, chief economist at the National Multi Housing Council, a Washington-based trade group.

He noted that the division between city and suburbs is blurring, too. There's no longer a clear line between an economic center where people work and suburban bedroom communities. Both can be home to major companies and residences.

Census data show that many closer-in suburbs linked to a city with public transit or well-developed roadways are benefiting from strong city growth, while far-flung areas near the metropolitan edge are fizzling after heady growth during the mid-decade housing boom.

Suburbs in the South and West also are seeing some gains, such as those around Houston, Phoenix, Las Vegas and Jacksonville, Fla.

New Orleans, which saw its population shrivel in the mid-2000s after Hurricane Katrina, continued to post the biggest increase in city growth relative to suburbs in the past year - 2.5 percent vs. 0.6 percent. Atlanta, Richmond, Va., Denver, Boston and Charlotte, N.C., also showed wide disparities between city and suburbs.

Other big cities showing faster growth compared with the previous year include Los Angeles, Chicago, Houston, Dallas, Phoenix, San Francisco and Columbus, Ohio.

In all, primary cities in large metropolitan areas with populations of more than 1 million grew by 1.12 percent last year, compared with 0.97 percent in surrounding suburbs. In 2011, the gap between city and suburb growth was narrower - 1.03 percent vs. 0.96 percent.

During the mid-decade housing boom, city growth had come to a standstill, while exurban growth rose by 2 percent, as the wide availability of low-interest mortgages pushed new residential development outward.

"The country has been exposed to a very difficult five years, and many people are reluctant to take chances," said Johnson, the University of New Hampshire demographer. "Marriages are still down, births are still down. Economists may say that the recession is over, but the recovery has not yet been fully reflected in demographic trends."

The Associated Press contributed to this report.