On March 31, 1995, the Social Security Administration (SSA) became an independent agency. SSA administers a national program of contributory social insurance. Employees, employers, and the self-employed pay contributions which are pooled in special trust funds. When earnings cease or are reduced because the worker retires, dies, or becomes disabled, monthly cash benefits are paid to replace part of the earnings the family has lost. Part of the workers contribution goes into a separate hospital insurance trust fund. This fund helps disabled workers, retirees, and their dependents with their hospital bills. They may also elect to receive assistance with medical expenses. This is done by the workers paying a percentage of supplementary medical insurance premiums. The Federal government pays the balance. Together, these two programs are often referred to as ""Medicare."" Medicare protection is also provided, under certain conditions, to Railroad Retirement beneficiaries based on a disability. The principal functions of SSA include, but are not limited to; research and recommendations oriented to the problems of poverty; health care for the aged, blind, and disabled; long-range planning, design, and development of SSA administrative plans; data processing systems used in establishing and maintaining records essential to its' various programs; statistical measurement and systematic evaluation of its' programs; policy guidance for the administration of the OASDI and SSI programs; and development of programs and materials to assure that Congress, Federal and State agencies, and the general public have an adequate understanding of the protections, rights, and responsibilities under SSA administered programs. In addition, SSA, through a world-wide organization of ten regional offices, six program service centers, and over 1,300 field offices, guides and directs all aspects of the cash benefit program operations of SSA.