Sen. Bernie Sanders (I-Vt.) has seen his support drop sharply among the young voters that have powered his rise in Democratic politics, according to a new poll.

The survey from Morning Consult finds that Sanders's support among people between the ages of 18 and 29 has dropped from 45 percent in March to 33 percent in May.

Sanders's support with the youngest voters, who propelled his surprising challenge to then-Democratic contender Hillary Clinton in 2016, has steadily declined in the poll since topping out at 46 percent in late February.

Overall, former Vice President Joe Biden has opened up a big lead over the Democratic field, coming in at 39 percent support among Democratic primary voters polled, followed by Sanders at 19 percent and Sens. Elizabeth Warren (Mass.) and Kamala Harris (Calif.) at 8 percent each. South Bend, Ind., Mayor Pete Buttigieg is at 6 percent and former Rep. Beto O'Rourke (D-Texas) is at 5 percent.

Biden's support among the youngest voter set has risen from less than 20 points last month to 24 percent in the latest survey. Warren has also seen an uptick among young voters, further contributing to Sanders's decline.

Biden leads in every other age group and his margins grow the older the electorate gets.

The former vice president leads Sanders by 7 points among 30- to 44-year-olds, by 23 points among those between the ages of 45 and 54, by 31 points with those between 55 and 64 years of age, and he leads by 43 points among those over the age of 65.

The Morning Consult online survey of 15,342 likely Democratic primary voters was conducted between May 6 and May 12 and has a margin of error of 1 percentage point.