Few states have enough money in their retirement systems to cover all the pensions they’re required to pay in coming decades.

Economic problems have decreased the value of their investments, and many states have simply failed to contribute their full share to retirement systems. Experts say retirement systems should have assets to cover at least 80 percent of the money they owe in the long run.

Here’s a look at the 10 states with the lowest funding percentages in 2010, according a new report from the Pew Center on the States: