During 2001-2006,heart disease and cancer were the main causes of death in the United States, accounting for nearly half of all deaths each year. During this period, or the age-adjusted death rate for heart disease declined 19.5%,from 247.8 per 100000 standard population to 199.4, and the age-adjusted cancer death rate declined 7.8%, or from 196.0 to 180.8. Changes in the other main causes of death were less pronounced.
Source: cdc.gov