The Associated Press
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Initiative 1240 is passing with about 51 percent of the vote, although the measure is failing in King County at about the same pace.
The state Secretary of State's office expects ballots to continue to arrive in the mail and county officials will keep on counting the thousands they have already received.
This is the fourth time charter schools been on the ballot in Washington state, where voters rejected the idea in 1995, 2000 and 2004.
If voters approve the measure, Washington would become the 42nd state to allow the public independent schools.