http://www.ssa.gov/retire2/fedgovees.htm
Until 1984, employment by the Federal government was covered under the Civil Service Retirement System (CSRS) and not by Social Security. If you worked for a Federal agency during these years, you did not pay Social Security tax on your earnings and those earnings are not shown on your record.
In 1984, a second retirement system--the Federal Employees Retirement System, or FERS--was introduced. People who began working for the Federal government in 1984 or later are covered by FERS instead of CSRS. Also, some workers who had been covered by the CSRS program chose to switch to the FERS program when it became available. Work under FERS is covered by Social Security.
If you stayed under the CSRS program after 1983, you still are not covered by Social Security but you are covered under the Medicare program and you pay Medicare taxes on your Federal earnings.
Your CSRS pension may affect your Social Security benefit amount. If you
