According to King County Elections spokesperson Kim van Ekstrom, her department expects to have about 180,000 ballots counted by 8 p.m. tonight. At 8:15 Elections will post the results thus far to their Web site. Since we no longer have things like exit polling, what with this all mail-in thing, we’ll have to rely on those results to be a representative sample of what we can expect from the rest of the ballots that get turned in.For the sake of context, and fun for numbers nerds, 180,000 ballots is about 16.5 percent of the 1.09 million ballots mailed out countywide. The Elections office is projecting 33 percent turnout overall. The returns have been a little on the low side so far so it might not get that high, but in general you can assume that we will know the results for about half of the votes expected to be cast. (Obviously the numbers are smaller for Seattle, where only 380,000 ballots were sent out, but 66,000 have been returned so far, so it’s a similar situation to the countywide picture.)With half the votes counted, anyone with a really big lead will probably go ahead and claim victory, but if any of the races are within a few thousand votes, it’s probably safer to consider it “too close to call” for tonight. Three hours and change left, start placing your bets!