Ever since Germany established its first Social Security system in 1889, the public retirement insurance has been "pay-as-you-go", with the current pensions of the retired paid from the current premiums of the not yet retired. Currently about 85% of the work force is enrolled in the Public Retirement Insurance (gesetzliche Rentenversicherung GRV). Civil Servants, who make up about 9% of the work force, have their own pension system and the self-employed, who make up about 9% of the work force, are mostly self-insured (but are allowed to participate in the GRV.)