Era
20th century
36
19th century
23
1783-1865
10
1961-1963
10
1775-1783
9
18th century
9
1933-1945
9
1945-1989
9
To 1775
9
1861-1865
8
1917-1963
8
1815-1861
7
1936-1953
7
1969-1974
7
1775-1865
6
17th century
6
1809-1865
6
1878-1953
6
1900-1999
6
1917-1936
6
Civil War, 1861-1865
6
Colonial period, ca. 1600-1775
6
1913-1994
5
1963-1969
5
1974-1977
5
1743-1826
4
1783-1809
4
1945-1953
4
To 1865
4
1735-1826
3
1751-1836
3
1767-1845
3
1837-1901
3
1849-1877
3
1884-1972
3
1908-1973
3
1913-2006
3
1918-1933
3
1946-
3
1951-
3
1953-1961
3
1953-1985
3
2009-2017
3
Revolution, 1775-1783
3
1592-1672
2
1757-1804
2
1758-1831
2
1782-1850
2
1783-1789
2
1789-1815
2
more ...