Life tables for the United States are based on those constructed by the Office of the Actuary of the Social Security Administration. The tables for single years (of both age and time) are the latest (as of July 1998) mortality estimates and projections for the U.S. "social security area." All other tables (for 5-year age groups and 5- or 10-year time periods) were derived from these tables. For multi-year time periods, the lx, dx, Lx, and Tx columns are the arithmetic average of the corresponding columns of the single-year tables; and the qx and ex columns are derived from the other columns in the standard fashion (qx=dx/lx and ex=Tx/lx). In a similar fashion, the "total" life tables are a simple average of the male and female life tables. Death rates are derived from each table by computing mx=dx/Lx.

A description of the methodology used to construct the SSA tables can be found in:

Felicitie C. Bell, Alice H. Wade, and Stephen C. Goss. Life Tables for the United States Social Security Area. Actuarial Study No. 107, SSA Pub. No. 11-11536, 1992.

Acknowledgements: Special thanks to Felicitie Bell for providing these data.