Social Security was intended to replace 40% of pre-retirement income, a goal it largely meets nationally, covering approximately 38% of retirees' expenses according to a FinanceBuzz report. However, the program's effectiveness varies significantly by state. In 24 states, Social Security benefits cover at least 40% of expenses, with Kansas and Oklahoma showing the highest coverage rates. This indicates that while the program provides a substantial base, its sufficiency as a sole retirement income source is state-dependent.