Year 1900: Life expectancy at birth was around 47.3 years.
Year 1920: Life expectancy at birth increased to approximately 54.1 years.
Year 1940: Life expectancy at birth further increased to around 62.9 years.
Year 1980: Life expectancy at birth saw a notable increase to approximately 73.7 years.
Year 2000: Life expectancy at birth continued to rise, reaching around 76.8 years.
Year 2020: Life expectancy at birth was estimated to be around 78.8 years.
These figures are approximate and are based on data from the National Center for Health Statistics and other relevant sources.
Life expectancy can vary by factors such as gender, race, socioeconomic status, and geographic location.