According to this article, an official of the Washington state Secretary of State’s office says the turnout in this month’s primary will be approximately 40%. If the final figures show exactly 40%, or lower, then that will be the lowest turnout in Washington state history in gubernatorial election years, at least back to 1936. Statistics for the number of voters registered in time for primaries, for years before 1936, were not preserved, so no one can calculate precise primary turnout earlier than 1936.
Washington state has always elected its Governors, and its other statewide executive offices, in presidential election years. Turnout (i.e., the number of people who vote in the primary, divided by the number of registered voters at the time of the primary) has been: 1936 64.11%, 1940 61.81%, 1944 44.27%, 1948 43.05%, 1952 53.43%, 1956 51.91%, 1960 49.64%, 1964 55.01%, 1968 44.98%, 1972 49.12%, 1976 43.24%, 1980 46.95%, 1984 40.31%, 1988 40.11%, 1992 45.80%, 1996 42.00%, 2000 40.80%, 2004 45.14%, 2008 42.60%.
Voting in Washington state is easier than ever, because for the first time in a gubernatorial year, this year every county sent every registered voter a ballot in the postal mail. Washington used the top-two system starting in 2008, and proponents insisted that turnout in primaries would rise. No incumbent is running for Governor in 2012, so one would have expected a higher turnout than in 2008, when the incumbent Democratic Governor was running for re-election, so there was no real contest in the Democratic primary in 2008.