Over 46 million people have already voted as of this writing, which is about 34% of the total number of people who cast a ballot in 2016. There's a good chance that turnout will be higher this time around so it might not quite be true that 1/3 of all voters in 2020 have already voted. But at this rate it does look like more than half the voters will vote before November 3. The outcome might already be a done deal no matter what shenanigans Trump tries to pull in the next two weeks.