While the number of Californians who log on to the Internet has increased since 2000 from 65 to 70 percent, a statewide survey conducted by the Public Policy Institute of California indicates there is a widening digital divide based on ethnicity, demographics and income.

Latinos and low-income residents are less likely to use computers and surf the Web than non-Hispanic whites and African Americans, according to the report.

The study, to be released today, found that 40 percent of Latinos have Internet access, and less than half own computers, compared with 86 percent of whites, 84 percent of Asians and 79 percent of African Americans.

Meanwhile, roughly half of households with an income of less than $40,000 have a computer, and even fewer get Internet access and broadband compared with more than 90 percent of more affluent Californians.

And fewer rural residents go online compared with Californians in urban areas.

The overwhelming majority across the state considers the Internet to be very important in everyday life, said Mark Baldassare, president of the Public Policy Institute of California.

"People who are already in a disadvantaged position become even more disadvantaged by not having access to the same information that other Californians do," Baldassare said. "I think that costs are a consideration for lots of people. The digital divide reflects basic differences in income and educational opportunities."

The study also found that while in the past eight years, computer usage has declined among Latinos, the majority use cell phones to send and receive text messages and access the Internet, signaling that mobile devices - which cost less than a computer and Internet connection - could help bridge the digital divide.

The poll was conducted June 3-17 in collaboration with the California Emerging Technology Fund as part of a series on public opinion and technology. Among its other findings:

-- 50 percent of Californians under age 35 use social-networking sites, compared with 20 percent in the 35-54 age group and 8 percent in the over-55 group.

-- 56 percent of parents visit their children's school Web sites.

-- 50 percent of residents say they get health information online, 55 percent get news about current events and 47 percent manage finances online and look for community events.

-- The report is based on a telephone survey of 2,503 California adults. It has a sampling error of plus or minus two percentage points.

E-mail Anastasia Ustinova at austinova@sfchronicle.com.