Voter registration is 536,670.
County Chairman and candidate John Eaves said in a statement 20 percent of Fulton County voters actually cast ballots in a primary election.
At that rate, 107,334 voters should be weighing in before polls close tonight at 7 p.m.
Early voters cast 12,489 ballots between April 28 and May 16, making the total so far 21,179.
Turnout will reach 20 percent when 86,155 more voters earn their I Voted stickers.
Of early ballots, 2,550 votes were cast at the south Fulton government service annex -- the most of any of the 12 advance voting sites -- and 260 at the College Park historical building.