The number of Californians registered to vote has reached a new high of 18.2 million, with nearly 77 percent of the state's eligible residents able to participate in Tuesday's election.

The updated figures, released Friday by Secretary of State Debra Bowen, marked California's first registration report since a new online system for signing up to vote launched in late September.

While the ability to register on the Web was touted as a way to dramatically expand the electorate, this year's growth in voter rolls ahead of the Oct. 22 registration deadline fell short of 2008 levels.

"This makes it clear that it's not just a question of making voter registration easier; it's really about what inspires people to care about their democracy and be part of the decision-making process," Bowen said in a statement.

At least one analysis, however, showed that the option to register online boosted the overall registration numbers in what would have otherwise been a lackluster year due to low voter enthusiasm.

Political Data Inc., a company that compiles voter information for campaigns and other organizations, found that more than 500,000 new voters signed up online during the last 45 days of the voter registration window. Traditional paper registrations accounted for nearly 636,000 new voters.

PDI Vice President Paul Mitchell said sites like Facebook and Twitter played a big role in the growth, pointing to the more than 200,000 voters who used the online system on the deadline day.

"The only way that people knew today was the last day to register, here's the link to register, go do it, was social media," he said.

But Mitchell and other observers caution that the rise in registered voters won't necessarily translate to a bump in ballots cast by Tuesday.

"It could be that (registering online) was easy to do, but it doesn't mean that these people are going to do mail ballots, which is the easiest way to vote, or take the time to vote on Election Day or even know where to go," said Tony Quinn, a political analyst.

Others believe the number of voters who took the initiative to sign up online suggests heightened interest in the issues on the ballot.

"Nobody called them and said, 'Hey you need to register to vote,' walked up to them in the mall or pestered them at the DMV," California Democratic Party Communications Director Tenoch Flores said. "These are people who on their own went and registered to vote online. These are highly motivated people."

Flores said the party has launched a late push to court those new voters, mailing pamphlets featuring its endorsements to 400,000 Californians who registered using the online system.

Democrats saw their share of the electorate rise slightly in recent months to 43.7 percent, a trend attributed in part to the introduction of the online system and aggressive registration drives by the party and organized labor.

Republican registration, meanwhile, continued to decline, dipping below 30 percent.

California Republican Party Chairman Tom Del Beccaro said the GOP did not make promoting the online option a priority, citing concerns about oversight and effectiveness of the system.

He said the drop was caused not by Republicans shedding their party label but conservative voters leaving the state.

Replacing those voters with young people, minorities and other demographic groups less likely to align with the GOP in California has proved difficult.

"I'm facing a tide of voters leaving the state and trying to replace them with demographics that are much more challenging for us," he said.

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