It was too close to call whether voters in much of Snohomish County approve of another 0.3 percent sales-tax hike to support Community Transit on election night.

Community Transit hasn’t lost a countywide ballot measure since it was established almost 40 years ago. Voters approved three previous 0.3 percent tax increases to pay for bus services in 2001, 1990 and 1976.

Initial election results show a slight majority of voters favor the measure aimed at generating about $25 million a year for the transit agency.

The Snohomish County Auditor’s Office released its first batch of ballot counts Tuesday evening. By about 8 p.m., about 16 percent of ballots had been counted.

CT’s tax hike had a slight edge, with 50.8 percent of votes cast in support of the measure, versus 49.1 percent against.

“It’s a nail biter,” said CT spokesman Martin Munguia. “But we’re definitely on the right side of that total.”

The county is expected to release updated election totals by 5 p.m. Wednesday. So far, ballot returns suggest a 33 to 35 percent voter turnout.

The 0.3 percent sales-tax increase for CT would add about 3 cents to a $10 purchase, starting in April 2016.

The money is intended to pay for improvements to existing service with extra buses and more trips, a second Swift rapid bus line, more commuter rides to downtown Seattle and University of Washington and new routes in Snohomish County.

CT’s taxing district includes most of the county’s urban areas, except Everett, which is served by Everett Transit. Much of the Highway 9 corridor is also excluded.

The agency already receives a 0.9 percent share of sales-tax revenue. The proposed increase would push its portion to 1.2 percent. Other than grants and fares, sales tax is CT’s sole source of money.

Opponents and supporters will be watching closely as ballots are counted in the coming days.

Mukilteo Mayor Jennifer Gregerson, who’s led the campaign in favor of the measure, said improving transit is important as the county grows. Bus service helps alleviate traffic congestion, she said.

Jeff Scherrer, who helped draft the opposing statement for voters pamphlets, said as the population swells, CT will receive more money from sales taxes without the increase. The Edmonds resident believes the agency needs to stretch its existing dollars and control expenses instead of asking everybody to pay more for their purchases.

CT wants to use about a third of the new revenue to pay for upgrades to existing routes with extra buses and expanded hours.

Another third of the money would support a second Swift rapid bus line built between Paine Field and the Canyon Park area of Bothell. It would be modeled on the one that runs along Highway 99.

The last chunk of revenue would pay for new bus routes, including commuter service to downtown Seattle and the University of Washington. Also added would be extra connections between the I-5 corridor and eastern Snohomish County.

Other proposed improvements include more service to job, housing and educational centers in Monroe, Stanwood and Arlington as well as new routes along Highway 9 between Marysville and south Everett.

Amy Nile: 425-339-3192; anile@heraldnet.com. Twitter: @AmyNileReports.