I have produced preliminary graphics comparing voter turnout for M66 and M67. Compared to what I would argue is the most comparable measure--the temporary income tax surcharge that Oregonians voted on in January, 2003, turnout in Multnomah County is lagging by 8%. I have also plotted the figures for the 2008 presidential contest to provide a bit of historical context.
I'm a bit reluctant to post the statewide figures yet because only three days of data are available at present.
The gap in the 2003 figure, by the way, is because they did not count any ballots on the King holiday.