NEW YORK (Reuters) - As the youngest members of the millennial generation became old enough to vote in this year’s U.S. presidential election, states and social media platforms poured efforts into online registration, hoping to attract these tech savvy voters who now rival Baby Boomers as the country’s largest demographic. With Election Day just two days away, political experts are skeptical that a record number of millennials who signed up to vote will actually result in the 18-34 year-old age group turning out at the polls in proportion to their relative size of the U.S. population. Millennials make up approximately 31 percent of U.S. citizens eligible to vote, according to the Pew Research Center, on par for the first time with Baby Boomers, who are typically aged 52-70 years old. There are an estimated 225.8 million eligible U.S. voters.   Millennials have so far, however, turned out in much lower numbers in elections than Baby Boomers. In 2008, a record year for millennial turnout, just 50 per cent of those eligible to vote did so, the National Census Bureau said. That compared with turnout rates of 69 per cent for Baby Boomers and 61 percent for people aged 36 to 51, also known as Generation X. This year, a number of efforts on social media by states and non-profits aimed to change that, including Facebook reminders on users’ accounts, Twitter hashtag campaigns, celebrities creating Snapchat and an Instagram post urging people to vote. According to a survey of state electoral officials and voter non-profits around the United States, these social media campaigns have paid off, at least when it came to getting young voters registered.  A survey of 2,000 millennials conducted by social media platform Yik Yak, which is known for its popularity among college students and teens, showed that 62 percent registered to vote for the first time this year and, of those, 9 percent registered online following a social media prompt. In California, roughly 31 per cent of all registered voters are now aged 18-35. A Facebook reminder on May 16 coincided with 143,255 people registering or updating their registrations online that day in the state, compared to an average of 23,166 per day that month, said California Secretary of State spokesman Sam Mahood. Other states reported similar spikes. In Oregon, more than 420,000 people registered to vote online in 2016, up from 2012 when 163,545 used the online system. Digital voter enrollments in Washington jumped by roughly 135,000 in 2016, compared to 2012. From January through mid-October this year, 381,318 people used the online system in Indiana, nearly three times as many as in 2012.  “Let’s face it - that’s where [younger voters] are; they’re on social media,” said Denise Merrill, the secretary of state for Connecticut, which used social media campaigns, including a dedicated hashtag and Facebook’s banner ads, to drive registrations. “Whatever we’re doing, we’re having pretty dramatic results.” Like a lot of experts, Donald Green, a professor of political science at Columbia University, is skeptical that an increase in young voter registration will correspond with millennials unseating the Baby Boomers as the most active voting bloc. Green conceded that there was “change afoot,” but said he thought it would far more gradual. By his estimate, it would be  25 years before millennials overtake Baby Boomers, or what he dubbed “generational replacement.” “In presidential elections the translation of new registration to votes is more like one half or one third,” he said. Michael Cornfield, an associate professor of political management at George Washington University, agreed that registering someone to vote does not guarantee they’ll show up on Election Day. “It’s up to the campaigns to do the last bit, which is to say make sure the right millennials in the right battleground states are being targeted,” said Cornfield. Some political experts said that, in general, millennials tend to vote more for Democratic Party candidates than Republicans. Laura Wray-Lake, an assistant professor at the University of California-Los Angeles, said the increase in millennial registration could be a boon for Democrats if they could harness some of the social media techniques used to register voters to get them to the polls.  With many political experts expecting overall voter turnout to be lower this year, millennial voters in swing states are a bloc that Democratic candidate Hillary Clinton could hope to turn out. Clinton leads Republican candidate Donald Trump by 27 percentage points among likely voters ages 18-34, according to a Reuters/Ipsos poll. “Young people have huge potential for political impact” Wray-Lake said. “I think eventually these millennials will be deciding the future of the country.” For a graphic on Online voter registration, click tmsnrt.rs/2fjdh4j 