OLYMPIA — A new poll released Thursday shows an exceptionally close race between Democrat Jay Inslee and Republican Rob McKenna in the final stretch of a campaign that’s considered to be one of the most competitive gubernatorial contests in the nation.The KCTS 9 Washington poll showed Inslee with a 47.9 percent to 44.7 percent lead over McKenna among registered voters, with 7.5 percent undecided. Among likely voters, Inslee and McKenna are nearly even, with Inslee holding just a 47.1 percent to 46.3 percent advantage over McKenna, with 6.6 percent undecided. In both camps, the numbers are within the margin of error, showing that the race continues to be very close.“The governor’s race is just an absolute tossup right now,” said Matt Barreto, director of the poll. “This makes it really interesting.”The telephone survey was conducted Oct. 1-16, sampling a total of 782 registered voters across the state, 644 of whom were considered likely voters. The margin of error for all voters is 3.5 percent; for likely voters, 3.9 percent.The poll, conducted by the University of Washington, also found voters supporting four ballot measures dealing with gay marriage, legalizing marijuana, approving charter schools and limiting taxes.Referendum 74 asks voters to either approve or reject a gay marriage law that was passed by the Legislature earlier this year. That law is on hold pending next month’s vote. The poll showed that 56.3 percent of registered voters back gay marriage in the state, compared to 35.6 percent who oppose it, with 6.1 percent undecided. Among likely voters, support decreased to 54.1 percent, with 38.4 percent saying they would vote against the measure, and 5.7 percent undecided.