Since 2000, the greatest racial/ethnic gainers in total eligible voters were Hispanics, from 7.4% to 13.3% of total eligible voters.
From 2004 though 2018, the number of vote-eligible Hispanics rose by 66% even though the entire population of the U.S, grew by only 10%.
A record 32 million Latinos are projected to be eligible to vote, exceeding the number of black eligible voters for the first time.
However, the turn out rate of Hispanics is relatively low. Since 1990, Hispanic turnout (actual voters / eligible voters) has averaged 15% below that of whites. So, even though Hispanic turnout increased by 40% between the two off-year elections of 2014 and 2018, it still in 2018 was only 40% vs. 56% for whites. In the presidential election in 2016, Hispanic turnout was 48% vs 63% for whites.
Complicating the picture for Democrats in 2020 is that in relatively few swing states there are many Hispanic voters.
For Democrats, Arizona is probably the state most important for high Hispanic turnout because of the relatively high Hispanic population (24% of all eligible voters, per Pew) and the chance to swing the election results from Republican to Democrat.
In five swing districts won narrowly by a Rep in 2018, the Hispanic electorate is at least 15%.