A head to head comparison of the Vermont 2020 Primary gives us an idea of the break down of the voters.
Bernie Sanders received 42% (79k votes) beating both Donald Trump who had 18%(33k votes) and Joe Biden who had 19% (34k votes) in the overall count of votes in Vermont if the election were among these 3 candidates.
Bernie Sanders wins 197 out of the counties in the state of Vermont to support his claims of his movement in the country. Donald Trump won 49 counties and Joe Biden won nothing.
These 10 counties play an important role in these primary elections. If a candidate can get a sizable majority in the biggest county (Burlington), it become very difficult to win majorities in the smaller counties with out voter outreach and increased voter participation in them. Bernie Sanders won these and the other 235 counties in the state of Vermont.
Bernie Sanders vs Joe Biden
Joe Biden vs Donald Trump
Donald Trump vs Joe Biden
In a head to head match up on just the total number of votes, Bernie Sanders (70%) beats Joe Biden (30%). Bernie Sanders (70%) beats Donald Trump (30%). Joe Biden (51%) beats Donald Trump (49%).
Bernie Sanders simply won the majority in all the top 10 counties. Joe Biden and Donald Trump could not achieve a victory since Bernie Sanders captures so many voters across most counties.