The ballot counting in Boulder County went off without incident Tuesday night -- a welcome change from the last two presidential elections.
As of 10:30 p.m., 111,048 ballots had been counted, amounting to 64 percent of the projected turnout. Clerk and Recorder Hillary Hall estimated Tuesday evening that 173,890 people voted in the county during the election.
"Everything is chugging along," Hall said around 10 p.m.
During the last two presidential elections, it took about three days before all the ballots cast in Boulder County were tallied. In 2004, poorly printed ballots slowed the process, and in 2008, flecks of paper dust flummoxed the optical scanning machines, requiring election workers to visually inspect thousands of paper ballots.
Even though the process moved relatively smoothly Tuesday night, Boulder County's counting process was likely slower than many other Colorado counties. According to Hall, that's a side effect of preparing the county's ballots for a thorough post-election audit.
In other counties, ballots that were counted during the election are recounted during the audit, but the results are not compared to the original counts on election night. Effectively, that process tests that the machines are working -- not that the ballots were counted correctly the first time around, Hall said.
But in Boulder County, the audit actually compares results to those from election night. To do that, however, the ballots must be processed in relatively small batches, slowing the counting process.
"Because we do our audit, getting everything read in takes longer," she said.
The large amount of mail-in ballots cast during this election also helped the counting process go more smoothly. Election officials estimated Tuesday that about 75 percent of all ballots cast in the county were mail-in ballots.
And as of Monday afternoon, about 115,000 mail-in ballots had already been returned, which allowed election workers to begin processing those ballots into the smaller batches necessary for the audits before Election Day.
An estimated 20,000 ballots were cast at polling places in the county Tuesday, Hall said.
Late Tuesday night, Hall said she expected that all ballots would be counted "by the wee hours" of this morning.