Fewer people are fleeing the once prohibitively expensive coastal reaches of Northern California, according to U.S. Census Bureau numbers released Thursday.

Santa Cruz County was among a number of greater San Francisco Bay Area counties that saw more U.S. residents staying put last year than any time since 2001.

For an explanation, observers say look no further than slumping home sales and slipping economic opportunity.

"For people to leave the most desirable areas, there has to be motivation to go, like jobs and housing," said Jim Chubb, a loan broker at Pacific Inland Finance in Soquel. "With the economy shrinking, that hasn't happened."

The draw of cheaper real estate inland is no longer an attractive investment as housing markets have plunged in places like Salinas and the Central Valley.

"People are saying we don't want to buy there. Others paid four [hundred thousand] and it's now worth three," said Chubb.

Indeed, this week's census data shows fewer new arrivals in areas of the state once associated with bargain housing.

In Santa Cruz County, the number of U.S. residents moving out between July 2006 and July 2007 is still greater than the number moving in, by 1,977, according to the census report. But that's just two thirds of how many left the year before and half of how many left the year before that.

Due to foreign immigration and more births than deaths, the county's overall population grew slightly between July 2006 and July 2007 -- from 250,523 to 251,747.

"As the housing market has tanked, people aren't so sure what they want to do," confirmed John Weeks, director of the International Population Center at San Diego State University. "They're not going to make precipitous decisions about new housing."

The trend to stay put since 2001 also follows in Santa Clara, San Mateo, San Francisco and Marin counties.