The State Department on Tuesday defended its estimate that it would take 75 years to fulfill a request from the Republican National Committee for emails of three top Hillary Clinton aides, and said that length of time is "not an outlandish estimation."

"That is an incredible number," State Department spokesman Mark Toner admitted. But he said the estimate is accurate because the RNC's request is "very complex."

"It's a very broad range involving a number of people over a period of four years, and it's not an outlandish estimation, believe it or not," Toner said.

The State Department said in a court filing that it would take about 75 years for it to release all the emails to three of Clinton's former aides: Cheryl Mills, Jacob Sullivan and Patrick Kennedy. The RNC is seeking those emails in a FOIA request.

According to CNN, the State Department said getting all the emails together from each official would take at least 16 years each, and in some cases, 33 years. State's filing indicated that it would only be able to find the emails sequentially, not concurrently, because of the backlog of FOIA requests.

"Given the Department's current FOIA workload and the complexity of these documents, it can process about 500 pages a month, meaning it would take approximately 16-and-2/3 years to complete the review of the Mills documents, 33-and-1/3 years to finish the review of the Sullivan documents, and 25 years to wrap up the review of the Kennedy documents — or 75 years in total," the department argued.