Story highlights The number of millennials is skyrocketing

But other age groups are more likely to vote

(CNN) No wonder Bernie Sanders is getting a boost at the polls: Millennials are now a voting force to be reckoned with.

Some 69.2 million Millennials are eligible to vote, roughly equal to the 69.7 million Baby Boomers who can cast a ballot, according to a new Pew Research Center report

The number of voting-eligible Millennials, those between 18 and 35 this year, has more than doubled over the past decade as the generation has grown into adulthood.

has been declining since its 2004 peak of 72.9 million. Gen Xers, who are between 36 and 51 years old, number only 57 million, or 25% of the electorate. Both Millennials and Baby Boomers account for about 31% of Americans who can vote, though the number of Baby Boomers, who are ages 52 to 70 this year,has been declining since its 2004 peak of 72.9 million.Gen Xers, who are between 36 and 51 years old, number only 57 million, or 25% of the electorate.

Millennial Democrats have lined up solidly behind the 74-year-old Sanders this election season, while older voters have gravitated to front-runner Hillary Clinton, 68, according to exit polls of primary voters.

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