Republicans continue to return their ballots at a faster rate than Democrats and unaffiliated voters in Colorado, but the gap is narrowing as Election Day approaches, according to the secretary of state’s office.

As of Friday morning, 612,589 voted ballots had been received by election officials, out of the state’s 3.37 million active registered voters. Registration in Colorado is nearly evenly divided between Democrats and Republicans, with unaffiliated voters having slightly higher numbers.

Voters have until 7 p.m. Tuesday to vote in person or to return their ballots to their county clerks – though election officials and the U.S. Postal Service stress that it’s too late to mail ballots, because they must be in hand by the time polls close, and postmarks don’t count. Find secure, 24-hour ballot drop-off locations at www.govotecolorado.com.

As is typical in nearly any election, older voters account for the majority of votes cast before Election Day. According to data released by the secretary of state, 56 percent of the ballots received through Friday morning were from voters over age 60. Just 3 percent of the total votes cast were from the very youngest voters, those age 25 and under. Slightly more women than men have returned ballots so far.

Republicans make up 39 percent of voters whose ballots have been received, compared with the Democrats’ 33 percent and unaffiliated voters’ 27 percent.

A year ago, with four days remaining in the presidential election, nearly three times as many ballots – 1,553,325 – had been received, and Democrats held a slight lead over Republicans for ballot returns.

Turnout in odd-year elections – known as “coordinated elections” as opposed to the even year’s General Elections – always lag, and this year is the first November election since 2009 without a statewide ballot question.

Six of Colorado’s 64 counties – Cheyenne, Dolores, Grand, Hinsdale, Mineral and Washington – aren’t even holding elections, because there are no contested races within their borders for school board, city council or local financial ballot measures. Some precincts in other counties won’t be voting this year either, because they aren’t situated in districts with contested elections, officials said.

El Paso County has seen the most ballots returned so far, with 83,902, followed by Jefferson County’s 67,735. Douglas County ranks third, with 54,636 ballots received; Denver is fourth, with 53,949; and Arapahoe County is next, with 50,449.

In last year’s election, 66 percent of voters returned their ballots to drop boxes, 27 percent mailed their ballots back, and 7 percent voted in person, according to Lynn Bartels, a spokeswoman for Secretary of State Wayne Williams.