https://www.nytimes.com/2020/03/02/opinion/bernie-sanders-2020-election.html

«About 37 percent of Democrats and independents under 35 voted in 2016. According to Broockman and Kalla’s figures, Sanders would need to get that figure up to 48 percent [11 points, for those who didn’t do the math yet — John L.]. By comparison, Broockman told me, in 2008, Barack Obama raised black turnout by about five percentage points.»