The percentage of California adults accessing items such as news and Facebook updates on their cellphones several times a day has doubled over the past two years, a survey released Wednesday shows.

More than nine out of every 10 adults in the state owns a cellphone and four out of 10 say they own a smartphone with a data plan. Latinos are twice as likely as white adults to rely on cellphones as their primary way to reach the Internet.

The findings from the latest Public Policy Institute of California survey on how Californians interact with the Internet also confirm that many Latino, low-income and older adults continue to live without the type of high-speed Internet access at home that 61 percent of likely voters say is a must-have utility.

Twenty-five percent of those polled say they access the Internet mostly with their cellphone. For those with a household income below $40,000, it jumps to 36 percent. For Latinos, it's 40 percent.

PPIC policy associate Dean Bonner said people relying on phones are missing out on consistent access to essential government websites or other applications that are not usually mobile-friendly.

"It gets them part of the way but it doesn't upgrade their experience all the way," Bonner said.

Millions of dollars in federal stimulus grants and additional state funding are aimed at bringing more Californians online through desktops and laptops at home. Broadband adoption at home grew at a slower rate than previous years, rising from 70 percent to 72 percent. The state's goal is 80 percent by 2015.

But almost one in five California adults do not use the Internet even though most live in areas where it can be purchased. Hundreds of community organizations are focused on helping them overcome barriers to purchase, from costs to poor understanding of the Internet's value.

"Rather than give up on those populations, we need to see how we can get them going," said Luis Arteaga, director of emerging markets for the nonprofit California Emerging Technology Fund, which helped pay for the survey.

One price incentive will arrive this fall. As part of its merger deal with NBC Universal, Comcast will offer Internet service for about $10 a month to new subscribers. Households with a child enrolled in the federal free lunch program will be eligible.

Arteaga said he's shown value to families by noting the cost savings from the use of Skype over high-speed Internet instead of calling cards over a regular telephone line.

Despite the sharp rise in cellphone usage across all racial and ethnic groups, younger, highly educated and affluent adults are the most likely to go online via cellphones.

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Call Paresh Dave, Bee Capitol Bureau, (916) 326-5543.

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