Chris Caskey, The Union Democrat

The U.S. Census Bureau released its population estimates for 2012 today, with both Tuolumne and Calaveras counties continuing the multi-year trend of population loss.

According to the Census statistics, Tuolumne County has a population of 54,008, down 1.2 percent from 2011 and 2.4 percent from the numbers reported in the 2010 census. In Calaveras County, the bureau reports an estimated a loss of 44,724 people, down almost 1 percent from 2011 and almost 2 percent since the census.

The numbers are similar to population losses seen in other Central Sierra Nevada counties like Amador and Mariposa, where job losses and foreclosures from a stagnant economy have driven residents elsewhere.

According to the Census Bureau, markets in Southern California and the San Francisco Bay Area have seen the most growth over the past year driven by strong economic activity. Stanislaus and San Joaquin counties, which have struggled economically with much of the Central Valley, also saw some moderate population growth.

"Southern California is numerically driving growth in California, along with the Bay Area," John Malson, a demographics researcher with the California Department of Finance, told The Union Democrat on Wednesday.

"The rest of the state, including (Central Sierra counties), clearly are not at the forefront of this increase," Malson stated in an email.

Tuolumne and Calaveras counties have both dealt with relatively stagnant growth for the past decade. Experts cite job losses as a major factor.

Population data from the 2010 Census showed that the county only grew by about 1.5 percent over the past decade. Calaveras County's population grew by only 1 percent.

The population report released today by the Census Bureau appears to confirm the correlation between population and the economy, as the regions and metropolitan areas showing the most robust growth have been bolstered by recent oil and gas exploration.

According to the Census Bureau, communities in west Texas, Wyoming, Kansas and North Dakota are among the 20 fastest growing metro areas in the country.

Census Bureau senior advisor Thomas Mesenbourg pointed out that almost half of the country's business growth in the oil and gas industries in the last year has taken place in the Permian Basin in Texas and North Dakota.

"No doubt the energy boom is playing a role," Mesenbourg said in a release.

Malson said the job market growth in Northern California is starting to move inland from the coast, into places like the Sacramento and San Joaquin valleys. That could make its way up the hill in time.

"More rural areas, where you would expect second homes or retirement growth to occur, have yet to see changes of this type. But the Baby Boom generation is on the verge of entering retirement in large numbers," he stated.