(Bloomberg) The number of tax-delinquent federal workers and retirees increased by 11.5 percent in 2011, according to Internal Revenue Service data.

The delinquency rate rose to 3.2 percent from 2.9 percent the previous year. The 311,566 delinquent taxpayers owe a total of $3.5 billion in federal taxes, according to the IRS data released today.

Among large executive branch agencies, the Department of Housing and Urban Development had the highest percentage of delinquent workers at 4.4 percent. The Treasury Department, which includes the IRS, had the lowest, at 1.1 percent.

Employees of the Board of Governors of the Federal Reserve System had a 5.6 percent delinquency rate, while active-duty military had a 2 percent rate.

Federal employees are more compliant in paying taxes than the U.S. population as a whole. According to the IRS, 8.2 percent of the population was delinquent on their federal taxes at the end of fiscal 2011, up from 7.8 percent the year before.

The delinquency rate at the Executive Office of the President was 2.1 percent, while the rates for employees of the U.S. House of Representatives and the Senate were 3.7 percent and 3.3 percent, respectively.

Highest Rates
The highest delinquency rates among federal employees were at two small agencies—the U.S. Commission on Civil Rights and the Morris K. Udall Scholarship and Excellence in National Environmental Policy Foundation. Both had a 9.1 percent delinquency rate, or four people at the rights commission and five at the scholarship foundation.

The House passed a bill last year that would require the government to fire federal workers who are “seriously delinquent” in paying their taxes. The bill, sponsored by Representative Jason Chaffetz, a Utah Republican, passed 263- 114, but didn’t advance in the Senate.

The data present a snapshot as of the conclusion of the 2011 fiscal year, which ended Sept. 30, 2011. It includes taxpayers who owe balances, haven’t filed tax returns and have balances deemed not collectible.