The economic proposals put forth by Republican presidential candidates Mitt Romney, Newt Gingrich and Rick Santorum would cause the national debt to swell.

Republican presidential candidate Ron Paul was the only candidate whose proposals would lower the national debt, according to a report released Friday.

The U.S. Budget Watch, a project of the non-partisan Committee for a Responsible Federal Budget, analyzed the impact the proposals made by the four candidates would have on the national debt through 2021.

The report breaks down how each part of the candidates' proposals would affect the national debt.

An analysis of President Barack Obama's proposals for the next term was not included in the report released Friday and the committee plans to release results of the same analysis of Obama's proposals at a later date.

The committee analyzed three scenarios for each candidate's proposals -- an optimistic low-debt scenario, an intermediate-debt scenario and a pessimistic deep-debt scenario.

Paul's proposals to reduce spending, cut taxes and change the size of the government would decrease the deficit by $2.2 trillion over the next 10 years. The committee estimates that Paul's proposals would cause the national debt to decrease to 76 percent of the GDP by 2021. In the low-debt scenario, which considers if Paul could follow through on canceling all of the federal debt held by the Federal Reserve System, Paul's proposals would cut the deficit by $4.3 trillion. A total of $1.9 trillion would be cut in the deep-debt scenario, according to the report.

Gingrich has proposed to cut both spending and taxes, which would increase deficits by $2.8 trillion on the optimistic side and $9.7 trillion on the pessimistic side. The middle scenario would increase deficits by $7 trillion and would cause the debt to balloon to 114 percent of the GDP by 2021, according to the report.

Proposals made by Santorum to decrease spending and taxes would cause the national debt to swell by $4.5 trillion by 2021 and would cause the national debt to be 104 percent of the GDP in 2021, according to the report. Optimistically, his proposals would reduce the deficit by $2.6 trillion, and pessimistically, would add $5.3 trillion to the debt.

Romney's proposals would add to the deficit, but not as greatly as Gingrich and Santorum. Romney's proposal to cut spending and taxes would add $250 billion to the national debt over the next decade in the intermediate-debt scenario and the debt would be 86 percent of the GDP in 2021. The low-debt scenario would reduce it by $2.2 trillion and the deep-debt scenario would add $2.2 trillion to the debt, according to the report.

The national debt now is $15.4 trillion and is 101 percent of the GDP.

The Committee for a Responsible Federal Budget is comprised of former staff of the Congressional Budget Committees, the Congressional Budget Office, the Office of Management and Budget and the Federal Reserve Board.