(credit: CBS)

(credit: CBS)

DENVER (AP) – Colorado voters were deciding on a major change to how public schools are funded Tuesday. A ballot measure asked voters to hike income taxes by about $1 billion a year in exchange for a raft of education upgrades.

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The prospects for the measure were far from certain.

Republicans and some business groups opposed what would be the largest voter-approved tax hike in state history. Democrats and teachers’ groups touted the measure as necessary to repair years of funding gaps for preschool through high school education.

Amendment 66 would raise state income taxes from 4.63 percent to 5 percent for taxable income up to $75,000 a year. Income above $75,000 would be taxed at 5.9 percent.

Colorado currently has a flat income tax of 4.63 percent. It moved to a flat tax in the 1980s, and the possible change to a progressive structure prompted some skepticism from business groups.

The measure makes significant changes to Colorado’s school tax funding formula. It would raise per-pupil school funding and backfill school budgets that were hurt by falling tax revenues during the recession. It would eliminate the state’s current “cost-of-living factor” funding boost and drive more money to districts with large numbers of at-risk students.

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The measure would also fully fund half-day preschool for at-risk students and give schools money to implement stricter teacher-tenure standards.

Both sides hoped to get their supporters to the polls for what was shaping up to be a low-turnout election. Early turnout was light, typical for an off year election.

“We’re in a really good place right now,” Curtis Hubbard, spokesman for the pro-tax campaign, said last week.

Opponents were feeling confident, too.

“They’re starting out with a huge financial advantage, but they are pushing a boulder uphill convincing people to support a huge tax increase,” said Ben DeGrow, an education analyst for the Independence Institute, a right-leaning think tank.

If the amendment fails, the schools funding debate may not be over. The funding changes, incorporated in a new law signed Democratic Gov. John Hickenlooper last spring, are valid until 2017, pending voter approval. That means the measure could return to ballots if voters reject it.

By KRISTEN WYATT, Associated Press

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