SAN DIEGO -- School-age children from Spanish-speaking homes in San Diego and throughout California are gaining English fluency at a fast rate but fluency among their elders is declining, it was reported Tuesday.

According to U.S. Census Bureau data, from 2000 to 2005, San Diego County's percentage of children ages 5 to 17 from Spanish-speaking households who speak English "very well" has jumped to 71 percent from 60 percent, the San Diego Union-Tribune reported.

Meanwhile, English fluency among adult Spanish-speakers dropped from 50 percent in 1990 and 2000 to 48 percent in 2005.

The census reported an even more precipitous decline for those 65 and older. The fluency rate for this group dropped from 45 percent in 1990 to 35 percent in 2005, according to the Union-Tribune.

Statewide, English fluency rates among Spanish-speakers across all age groups largely mirror those in San Diego County, the newspaper reported.

Experts explained the decline in fluency among adult Spanish speakers by pointing to the existence of established San Diego County immigrant communities where adults can get by with only basic English or none at all, the newspaper reported.

The increase in student language ability can be explained by a big push among school districts to boost English fluency, and school officials credit new laws at the federal and state levels for the improvement, according to the Union-Tribune.

Proposition 227, which California voters passed overwhelmingly in 1998, changed the focus of schools from bilingual education to an English-immersion model.