The poverty rate in San Diego County reached to its highest level in 50 years in 2008 — rising to 12.6 percent from 11.1 percent the previous year, according to an analysis released Tuesday by the Center on Policy Initiatives.

There were 367,000 San Diego County residents living below the federal poverty line in 2008 — 46,000 more than the year before, according to CPI, which compiled its analysis using recent data from the U.S. Census Bureau.

“The problem is not only the increase in unemployment, but a growth in working poverty as more people have had their hours cut to part-time, ” said Murtaza Baxamusa, CPI’s director of research.

Those living below the federal poverty level make less than $10,991 a year for an individual or $21,834 annually for a family of two adults with two children, according to CPI.

Imperial County has the state’s highest poverty rate, with 22.9 percent of people living below the federal poverty level last year, CPI reported.

The nonprofit research organization promotes policies to improve the pay and benefits for San Diego County’s workers.