Voter turnout exceeded our projections during the August 2018 Primary Election, which marked the first time voters did not need a stamp to mail in their ballots. King County Elections projected a 40 percent turnout rate, based on historical data and slightly adjusted to account for potential voter behavior changes due to prepaid postage. Actual turnout was 43.4 percent, the highest rate of voter participation since the 2004 primary election!
The availability of prepaid postage also led to more voters returning their ballots through the mail. In recent general elections, a majority of voters favored ballot drop boxes, especially as we added additional ones (61 and counting!) But during the August 2018 primary, more than two-thirds of all voters returned their ballots by mail.
We saw this same reversal of voter behavior when we piloted prepaid postage during the February and April 2017 special elections. In both elections, a majority of voters chose to mail their ballots. And turnout was about 8 points higher than our projections.
You can put away your book of stamps for now. Prepaid postage will be available again for the November 2018 General Election.
Election Connection 
Really glad to hear this so now we need to keep paying postage. Especially for rural, elders and handicapped. Way to go King County!