30 years is considered one generation
Robert Berry Family And National Facts Indexed By Year
30 Year Intervals:
- 1700 to 1750
- 1751 to 1780
- 1781 to 1810
- 1811 to 1830
- 1831 to 1860
- 1861 to 1890
- 1891 to 1920
- 1921 to 1950
- 1951 t0 1980
- 1980 to 2008