ST. PAUL — The average rate for policies sold on Minnesota’s health insurance exchange will go up 4.5 percent in 2015 but remain the lowest in the nation, state officials said Wednesday.

The four holdover companies — Blue Cross Blue Shield of Minnesota, HealthPartners, Medica and U-Care — submitted average rates that ranged from a 10 percent decrease to a 17 percent increase. A fifth company will join the exchange in 2015, Blue Cross affiliate Blue Plus.

The lowest-cost and largest provider in the exchange’s first year, PreferredOne, said last month it was dropping out because it couldn’t sustain its pricing.

“We expect no other state will release rates lower than Minnesota,” Commerce Commissioner Mike Rothman said. “We achieved the lowest rates even though last year’s lowest-cost company decided to sit out this year.”

The rate announcement was a politically charged event. Republicans earlier this year accused Gov. Mark Dayton of trying to delay it until after the November election. On Wednesday, Senate Minority Leader David Hann argued the average was misleading and that many consumers will pay much more, especially with PreferredOne’s departure.

At a news conference, he passed around a price chart for a 25-year-old in the metro area that showed monthly premiums at four different coverage levels rising from 18 percent to 37 percent.

“I think the 4.5 percent rate increase is completely bogus,” Hann said.

Dayton said he was pleased by the number, and noted it doesn’t factor in subsidies that some people can get. He said most people will see a “very modest” increase and many will pay less.

“I realize we’re 34 days before an election but it is permissible to actually recognize and even applaud good news,” Dayton said.

A check of some individual rates in the state’s nine zones found a mix of rates. For a 40-year-old in southern Minnesota, the bronze plan would rise 36 percent; the silver plan would go up 17 percent; the gold plan would rise 15.5 percent; and the platinum plan would go up 23 percent.

But for a 25-year-old in southeast Minnesota, the monthly rate would rise 5.4 percent on the bronze plan; fall 4.3 percent on the silver plan; fall 0.1 percent on the gold plan; and rise 5.5 percent on the platinum plan.

Those comparisons don’t include subsidies. MNsure chief executive Scott Leitz encouraged consumers to shop early for policies, and he said more people will qualify for tax credits in 2015 than this past year.

State officials said consumers will have more choices, and highlighted southeast Minnesota, with more than 30 products in 2015 compared to fewer than 10 this year. The number of individual plans statewide will increase to 84, up from 78.

Leitz and Dayton both said the state is better prepared for the next open enrollment period that begins Nov. 15. Leitz said the MNsure website has added capacity to load more quickly, and the state will have some 300 call-center representatives, compared to 30 when the exchange launched.