Adult mortality rate is the probability of dying between the ages of 15 and 60--that is, the probability of a 15-year-old dying before reaching age 60, if subject to age-specific mortality rates of the specified year between those ages.
(1) United Nations Population Division. World Population Prospects. New York, United Nations, Department of Economic and Social Affairs (advanced Excel tables). Available at http://esa.un.org/wpp/unpp/panel_population.htm, (2) University of California, Berkeley, and Max Planck Institute for Demographic Research. Human Mortality Database. [ www.mortality.org or www.humanmortality.de].