How secure are federal workers’ jobs? According to a recent USA Today study, death is the leading cause of job loss in 15 federal agencies.

The federal government laid off or fired 0.55 percent of its workforce, according to USA Today – about one sixth of the firing/layoff rate in the private sector. A pair of agencies, the Federal Trade Commission and the Federal Communications Commission, did not fire or lay off a single worker in the budget year that ended September 30, despite employing roughly 3,000 workers between them.

Federal workers based in Washington DC were least likely to be fired or laid off – only 0.26 percent lost their jobs.

A spokesperson from the Department of Housing and Urban Development, which fired or laid off only 0.15 percent of its workforce, attributed the low turnover rate to the extraordinarily high quality of HUD employees. “We’ve never focused on firing people, and we don’t intend to start now,” the spokesman told USA Today. “We’re more focused on hiring the right people.”

If private employers would put the time and effort into hiring the right people, in other words, their turnover rates might be comparable.

The USA Today reveals some other interesting facts about federal employment:

USA TODAY found that nearly 60% of firings occur in the first two years of employment, mostly workers on probation and outside the federal job protection system. Blue-collar workers are twice as likely to be fired as white-collar employees. The federal government’s 12,700 food preparation workers had the highest rate of getting fired last year — 2.5%.

White-collar federal workers have almost total job security after a few years on the job. Last year, the government fired none of its 3,000 meteorologists, 2,500 health insurance administrators, 1,000 optometrists, 800 historians or 500 industrial property managers.

The nearly half-million federal employees earning $100,000 or more enjoyed a 99.82% job security rate in 2010. Only 27 of 35,000 federal attorneys were fired last year. None was laid off. Death claimed 33.

Job security actually represents one of the chief advantages that public sector workers enjoy over their private sector counterparts, a fact noted by the Heritage Foundation’s James Sherk last year:

Civil service rules make it prohibitively difficult to fire federal employees for bad performance once they pass their probationary period—one year on the job. Most federal employees who perform poorly never get fired. They keep their jobs unless their supervisor works through an arduous process of exhaustively documenting their performance and working through a complex appeal process.

The result: exactly the trends documented by USA Today.