Life expectancy is the average number of years a human has before death, conventionally calculated from the time of birth, but also can be calculated from any specified age. Advances in sanitation, nutrition, and medical knowledge made possible incredible changes in life expectancy throughout the world, providing subjects for study as well as the need to study them. In the United States, only 50 percent of children born in 1900 reached the age of 50; life expectancy today is approximately 77 years of age. But note that there is a big discrepancy between males and females, 73.6 years for men and 79.4 years for women. Life expectancy is lower for African Americans; 67.2 years for men and 74.7 years for women (Hoyert, Kochanek, and Murphy, 1999). ...more from Wikipedia
- Between 1998 and 2000, 44 different countries had a change of two years or more of their life expectancies.
- Life expectancy changes as one gets older.
- The top three causes of death are heart disease, cancer, and stroke.