The Congressional Research Service has examined federal retirement data in several reports, finding that the FERS system continues to cover ever-larger shares of active employees and retirees, but that employees under it tend to retire at older ages than do employees under the CSRS system.

One report said that in 2009, 20,219 employees retired with immediate annuities under FERS, at an average age of 63.2 years and an average length of federal service of 20.2 years. In contrast, the average age of the 37,635 CSRS retirees under normal voluntary retirement was 60.2, with an average of 34.8 years of service.

Thus, FERS employees tend to retire at an older age but with fewer years of service.

“The average length of service for workers retiring under FERS will rise over time as the proportion of federal employees who spent their entire careers under FERS continues to increase,” said the report.

Some employees still hold the opinion that the traditional CSRS program is the dominant federal retirement system. However, the report noted that 1995 was the first year in which the percentage of workers covered by FERS exceeded the percentage of those covered by CSRS. FERS is growing and CSRS is shrinking for the simple reason that employees first hired after 1983 are placed in FERS, CRS said.

The report added that FERS crossed the 75 percent representation mark in fiscal 2006; today its share stands at about 82 percent.