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 current age-specific mortality rates 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].