Updated

As Republican presidential candidates Mitt Romney and Newt Gingrich parse the details of their individual tax returns, hundreds of Capitol Hill employees are taking taxpayer dollars to the bank without paying their share.

Internal Revenue Service data show that 3 percent of Senate staffers and more than 4 percent of House staffers owed taxes in 2010, adding up to about $10.6 million in unpaid taxes. More than 98,000 civilian federal employees were delinquent on their taxes in 2010, adding up to more than $1 billion in taxes owed, according to the IRS.

Rep. Jason Chaffetz, R-Utah, last year introduced a bill to require federal employees to be fired if they are "seriously delinquent" on their taxes. Seriously delinquent is defined as outstanding federal tax debt for which a public lien has been filed. The bill was passed by committee in June but is still waiting for a vote from the full House.

"If you work for the federal government and you don't pay your taxes, you should be fired," Chaffetz said in a statement provided to FoxNews.com. "It is totally unacceptable to live on the federal payroll and not pay your taxes.  The Obama administration has totally ignored this cheating. Congress should pass my bill and hold federal workers accountable."

Under current law, only IRS employees can be fired for not paying their federal income taxes, according to Chaffetz's office.

Sen. Tom Coburn, R-Okla., in 2010 introduced a similar bill, to make delinquent taxpayers ineligible for federal employment.

"Legislators and government employees should not be exempt from the laws they write and enforce," Coburn said when introducing the bill. "The very nature of federal employment and the concept inherent to 'public service' demands those being paid by taxpayers contribute their fair share of taxes. They should lead by example."

The number of civilian federal employees delinquent on their taxes has been on a downward trend since 2004, but the amount owed has increased significantly -- from just under $600 million in 2004 to more than $1 billion in 2010.

About 2 percent of active duty military and military reservists owed a total of nearly $340 million in taxes in 2010. About 2 percent of retired civilian federal employees and almost 4 percent of military retirees owed a total of $2 billion.