The Civil Service Retirement System (CSRS) and the Federal Employees Retirement System (FERS) are the two primary retirement systems for federal employees. Established in 1920, CSRS was the original system, providing a defined benefit pension. In 1987, FERS was introduced to replace CSRS for new federal employees, offering a combination of a basic pension, Social Security, and the Thr... https://www.federalpensionadvisors.com/post/how-many-retirees-are-under-csrs