A new report released Tuesday by the Manhattan Institute finds the teachers pension plan is underfunded by as much as $36 billion.

That's more than twice what is being reported by the city.

The report finds nationally the pension plan is only 54 percent funded. The city is even lower with only 46 percent.

"That's something that is going to have to be made up by taxpayers in the future," said Josh Barro of the Manhattan Institute. "These are obligations to teachers that have to be paid out -- they're contractual. So the fact that the money is not there, it's not teachers that bear the burden, it's all these taxpayers who bear that burden will have to pay higher taxes in the future to bear that burden."

The institute blames the funding gap on pension systems overestimating their returns on investments.