WASHINGTON (Reuters) - With their candidate on the ropes, supporters of Bernie Sanders again failed to show up when it mattered on Tuesday as Democrats held six presidential nominating contests, including the big prize of Michigan, according to exit polling by Edison Research.

Democratic U.S. presidential candidate and former Vice President Joe Biden speaks during a campaign stop on gun violence in Columbus, Ohio, U.S., March 10, 2020. REUTERS/Brendan McDermid

Edison declared former Vice President Joe Biden the winner over Sanders, a U.S. senator from Vermont, in Michigan, Missouri, Idaho and Mississippi after voting ended in those states.

Young voters and white men - two groups among whom Sanders has attracted strong support - made up roughly the same proportion of turnout as they did in 2016 in Michigan, Missouri and Mississippi, the three states where Edison has data in both years.

And a large majority of African Americans in those states voted for Biden, despite Sanders’ last-minute endorsement from civil rights activist Jessie Jackson.

Sanders, a progressive stalwart who has been buoyed by his support for increasingly popular proposals like Medicare for All, which would replace private health insurance with a government-run plan, has based his candidacy on the notion that he could drive up voting among people who tend to stay away from politics.

So far, that has not happened in many of the states that have voted this year. Biden won the lion’s share of the delegates in last week’s Super Tuesday contests when 14 states voted.

Edison, which compiles voter polls and live election results for media organizations including ABC News, CBS News, CNN, NBC News and Reuters, also found that a majority of voters said Biden was the candidate they trusted most to handle a major crisis, a sentiment that may be weighing heavily as coronavirus cases spread across the country.

The respiratory illness has killed 29 people in the United States and infected nearly 1,000 people, with nearly three-quarters of the 50 U.S. states reporting cases. Its swift spread across the globe has forced many school closures, event cancellations and cutbacks in business travel.

Stocks on Monday suffered their biggest one-day drop since the 2008 financial crisis before recovering somewhat on Tuesday.

Edison found that when it comes to confronting a major crisis, about 44% of voters in Washington state, 50% in Michigan and 61% of voters in Missouri said they trusted Biden.

About three in 10 Democratic primary voters in each of those states said they trusted Sanders more than Biden.

Here are other highlights from Edison’s exit polling in Michigan, Missouri, Mississippi and Washington. Edison did not conduct voter surveys in Idaho or North Dakota, which also held nominating contests on Tuesday.

The proportions may change as more polling is conducted and votes are tallied.

** Sanders won large majorities of voters under 30 years old in many primary states this year, including Michigan and Missouri on Tuesday. Yet that group had a smaller impact on the results. Voters between 18 and 29 made up 14% of the Democratic primary electorate in Missouri and 16% in Michigan, down a few percentage points in each state from 2016.

** African Americans mostly voted for Biden. Barack Obama’s former vice president won 87% of the black vote in Mississippi, 72% in Missouri and 66% in Michigan.

** In Washington, Biden appears to have made most of his gains in support in the last few weeks. Sanders had a comfortable lead among those Democratic primary voters who made up their minds last year, beating Biden by a 3-to-1 margin. Yet Biden beat Sanders by nearly the same 3-to-1 margin among those voters who decided in March.

** 38% of voters in the Washington state Democratic primary said they were “very concerned” about the coronavirus outbreak, and those who were the most concerned supported Biden over Sanders by nearly a 2-to-1 margin. Washington has been the hardest hit by the health crisis of any state, with 24 deaths, nearly all of them in the greater Seattle area.

** Neither Sanders nor Biden can claim to have the more energized supporters. In the Washington state Democratic primary 32% of voters said they would be ‘enthusiastic’ if Biden wins the nomination, while 35% said they would feel the same way if Sanders won. In Missouri, 42% of voters said they would be ‘enthusiastic’ if Biden wins the nomination, versus 32% who would feel the same if Sanders wins. In Michigan, 31% of Democratic primary voters said they would be ‘enthusiastic’ if Biden wins the nomination, while 39% said the same if Sanders wins.

** Most Democratic primary voters said they would line up behind the party’s nominee regardless of who it is. That includes 89% of voters in Washington, 86% of voters in Missouri and 82% in Michigan.

** Only a small minority of Democratic primary voters said they would be “upset” if either Sanders or Biden won the nomination. One out of 10 voters in Washington and Michigan said they would be ‘upset’ if Biden won, while two of 10 said they would feel the same if Sanders wins.

** Thirty-three percent of Democratic primary voters in Michigan said they made up their minds in the last few days, compared with 20% in Mississippi and 27% in Missouri.

** Healthcare was the top issue in each of the states surveyed on Tuesday. Forty-three percent of Democratic primary voters in Michigan, 47% in Missouri, 42% in Mississippi 37% in Washington named healthcare as a bigger concern than climate change, race relations or income inequality.

** Among voters naming healthcare their top issue, a majority backed Biden in Michigan, Mississippi and Missouri.