State-run pension systems across the country were underfunded by $1.2 trillion last year and are expected to be in even worse shape in the years ahead, according to a report released Thursday from a top credit rating agency.

Moody’s Investors Service said it expects the gap to hit $1.7 trillion with the next round of state audits, largely because investment returns have been far below expectations for the funds.

The report is among the first to aggregate state government pension liabilities under new accounting rules that are intended to provide a more accurate picture of the funds’ fiscal health.

Moody’s conclusions are similar to other recent reports from experts in the field and Standard & Poor’s, another rating agency: The states with the largest gaps will have to plow far more money into their pension systems each year just to keep the problem from getting worse.

Lower-than-expected investment returns, growing numbers of retirees and longer life spans are expected to widen the liabilities in the years to come. Closing the gap generally means raising taxes or diverting money from other areas of a state budget, solutions that are not politically popular.

Kentucky, for example, has been increasing contributions to try closing a $36 billion gap in its pension fund. But that comes with a price: The higher payments have been coupled with sharp budget cuts, particularly in higher education.

New Jersey contributed just over 2 percent of its revenue to pensions, an amount below the nationwide median. Just to keep its $90 billion gap from growing, the state would have to quadruple that amount. Doing so would eat up nearly 10 percent of the state’s revenue.

New Jersey is among five states that account for more than half the total pension liabilities nationwide. The others are California, Illinois, Pennsylvania and Texas.

The Moody’s report said no state had a fully funded pension system, although some states were close, including Florida, North Carolina and Wisconsin.

Moody’s compiled information for most states based on audits of their 2015 fiscal years. The findings are not directly comparable to past reports because of the accounting change.

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