The Obama administration on Thursday released a report showing that federal employees who did not work during the government shutdown were paid $2 billion.

The Office of Management and Budget report found that government employees were furloughed for a total of 6.6 million days, eclipsing any other government shutdown in U.S. history. Administration officials say those furloughs led to about $2 billion in lost productivity -- equal to the amount federal workers were paid for a period when they did no work.

Furloughed government workers received backpay for the days they missed in the deal struck to reopen the government.

The report also found that October’s government shutdown will cause the nation’s economy to shrink in the fourth quarter of 2013, pointing to about 120,000 fewer private sector jobs and billions of dollars in lost output.

“The shutdown that occurred last month inflicted completely unnecessary damage on our economy and took a toll on families and businesses across the country,” OMB Director Sylvia Mathews Burwell said. “These costs include economic disruption, negative impacts on federal programs and services that support American businesses and individuals, costs to the government, and impacts on the federal workforce.”

The OMB report said that fourth-quarter gross domestic product would decrease between 0.2 and 0.6 percentage points.

The shutdown lasted for 16 days in October, as the White House and Congress failed to reach an agreement to keep the government funded. Both sides will again need to reach a new resolution to continue funding the government by mid-January to avoid another shutdown.

Among the examples of lost productivity cited by OMB:

The Bureau of Land Management was unable to process about 200 applications for drilling permits.

More than two million liters of U.S. products were not shipped from American ports, as import and export licensing was put on hold.

The Internal Revenue Service could not process 1.2 million income-verification requests, possibly delaying mortgage and loan approvals.

There was roughly $500 million less in visitor spending thanks to the closure of national parks and museums.

About $4 billion in tax refunds were delayed and tax-filing season next year will be pushed back by up to two weeks.

The report was released as Republicans and Democrats on Capitol Hill try to negotiate a longer-term spending and debt ceiling deal. Both sides have said they want to avoid another shutdown but still remain far apart on any potential “grand bargain.”