There is at least one Libertarian on the ballot across the U.S, in areas containing 81.9% of the voters, for the November 2010 election. The Libertarian Party, as is usual in midterm years, is on the ballot in more places than any other minor party.
For 2010, the equivalent percentages for other leading minor parties are: Green, 54.6%; Constitution, 39.0%; Working Families, 8.8%. Of course, most of the Working Families Party nominees are also Democratic Party nominees.
Also, 7.3% of the voters will see a candidate on the ballot with the Tea Party label, but there is no nationally-organized political party with that name. Voters will see the Tea Party label in Florida, Nevada, and in a single U.S. House district in New Jersey. And, 9.5% of voters will see an Independence Party nominee on their ballots, but there is no national political party with that name, just three particular state parties in Minnesota, New York, and South Carolina.