Since 1970, U.S. life expectancy has gradually increased by 11%. In 2010, the average American lived to be about 78.7 years of age in comparison to the average lifespan of 70.8 in 1970, according to a recent CDC/National Center for Health Statistics report.

The difference in life expectancy between white and black populations has also narrowed to a 3.8 year gap in 2010, compared to 7.6 years in 1970.

In 1900, the gap was 14 years — the average black male lived to be about 32.5 years old, and white males averaged 46.3 years old. Black females' lifespans remained at about 33.5, and white females were expected to live for about 48.3 years.

Though the life expectancy of both the white population and black population increased by 10 percent and 17 percent, respectively, a gap in life expectancy of 3.8 years still remains between the two populations. According to the report, the disparities between the two populations can be "examined to determine which leading causes of death contributes most to the differences."

The remaining 3.8-year gap between the white and black population can be explained by death rate disparities — the black population overall is more likely to be affected by heart disease, cancer, homicide, as well as diabetes. "Higher heart disease mortality for the black population accounted for a loss of 1.007 years in life expectancy," the report states.

However, the black population experienced a lower death rate than the white population when it came to suicide, Alzheimer's disease, and chronic lower respiratory diseases such as bronchitis, emphysema, and asthma.

For black females, higher death rates due to heart disease, cancer, diabetes, and stroke caused the 3.3 age gap between white and black females. Black females also had less of a chance of dying from chronic lower respiratory diseases, Alzheimer's disease, suicide, and chronic liver disease compared to white females.

Overall, the female population boasts a longer life expectancy than that of males, with white females averaging 81.3 years of age, and black females averaging 78 years of age. The average life expectancy of white males is 76.5, with black males at 71.8.