IOWA CITY (AP) — An Iowa City-based group claims Iowa’s tax revenues can’t keep up with long-term spending and argues the state should consider changes to raise more money.

In a report released Monday, the Iowa Fiscal Partnership predicted Iowa’s revenue will remain stagnant as education and health care costs continue to rise. It noted the state could offset some of those increased costs by changing corporate tax rules and tax policies for seniors.

The fiscal partnership is a joint initiative of the generally liberal-leaning Child and Family Policy Center and The Iowa Policy Project.

Peter Fisher, one of the study’s authors, said that in the coming decades, the state will spend more on education and health care even as its population ages and its share of school-age children shrinks. Cutting spending could be difficult, and the state could increase taxes by a closer look at where and how it gets its money, he said.

“However bleak things look now, the long-run prognosis isn’t particularly cheery,” Fisher said. “We need to take that into account when we think about what policies we adopt in the short-run to account for the current economic downturn.”

The study pointed to a proposal backed previously by Gov. Chet Culver to close what he called a loophole that allows multi-state businesses to report profits from Iowa operations in states that have a lower — or no — corporate income tax. Lawmakers have shown little interest in Culver’s proposal.

The report also suggested considering changes to tax rules that give elderly Iowans a break by taxing pensions and Social Security at a lower level.

The aging population will account for a 2 percent to 3 percent drop in state income tax revenue, the report states. Eliminating tax breaks for seniors would boost income-tax revenue, with a peak of about $2.2 billion in 2015. If the tax breaks are left in, the report claimed, the state would lose $40 million in income-tax revenue by 2030.

“What we’re doing is we’re taxing more and more lightly the share of the population that’s growing most rapidly,” Fisher said. “That’s going to hit home in the next 10 to 20 years because of those tax preferences.”

The partnership said Iowa’s long-term state revenues need to be examined because its tax base could shrink at a time when its population is growing at one of the nation’s lowest rates.

The report claimed that Internet sales could worsen matters because taxation of such transactions is “spotty, at best.” The report estimates losses in Iowa due to Internet purchases at between $155 million and $243 million per year.