Life expectancy at birth is often used to appraise the overall health of a given population and to make comparisons between different populations (NCHS, 2019a). Changes in life expectancy over time are commonly used to describe trends in mortality. Life expectancy is the average number of years at birth a person could expect to live if current mortality trends were to continue for the rest of that person’s life.

This indicator is based on data from the National Vital Statistics System, which registers virtually all deaths and births nationwide. The temporal coverage of this indicator is from 1940 to 2017 and data are collected from all 50 states and the District of Columbia.

Exhibit 1 presents the historical trends in life expectancy at birth for the entire population as well as by sex, race, and ethnicity between 1940 and 2017, showing an upward trend in life expectancy in the U.S. over time. Life expectancy at birth has increased throughout the 20^th century and into the 21^st century. The highest overall life expectancy of 78.9 years was recorded in 2014, with a slight decrease to 78.6 years in 2017.

For all races and ethnicities combined, life expectancy increased over time. For example, over the most recent 10-year data period, life expectancy increased for both males (75.6 years in 2008 to 76.1 years in 2017) and females (80.6 years in 2008 to 81.1 years in 2017). The gap in life expectancy between males and females was greatest (7.8 years) in 1975 and 1979. This gap has continued to slowly narrow through 2017, with life expectancy 5 years longer among females compared with males.

Race and ethnic-specific analyses also show increases over time within all groups, remaining somewhat stable in recent years. For the most recent 10-year data period, life expectancy among blacks increased from 74.3 years in 2008 to 75.3 years in 2017. However, life expectancy in 2017 continued to be higher in whites (78.8 years) compared to blacks (75.3 years). Also in 2017, white females continued to have the highest life expectancy among racial groups at 81.2 years, followed by black females at 78.5 years, white males at 76.4 years, and black males at 71.9 years. Life expectancy has also increased from 2008 to 2017 among Hispanics (80.8 to 81.8 years), non-Hispanic whites (78.4 to 78.5 years), and non-Hispanic blacks (73.9 to 74.9 years) (Exhibit 1).

• Life expectancy at birth is strongly influenced by infant and child mortality rates. It is important to consider such influences when making comparisons among subgroups, as differences in life expectancy among certain subgroups may be mostly attributed to differences in prenatal care and other important determinants of infant and child mortality.

• Life table data presented for years prior to 1997, from 1997-1999, from 2000-2007, and from 2008 onward are based on slightly different methodologies. In most cases the differences are quite small, but it is important to note these changes.

The annual life expectancy data used for this indicator were obtained from the life tables report published by CDC’s National Center for Health Statistics (NCHS, 2019b). Life table methodologies used to calculate life expectancies are presented in the NCHS report.