Era
20th century
45
19th century
34
Civil War, 1861-1865
25
1933-1945
18
1918-1945
14
21st century
14
1945-
11
1882-1945
10
18th century
8
1929
8
1989-
8
1945-1989
7
2001-2009
7
1900-1999
6
1946-
6
1706-1790
4
1743-1826
4
1961-1963
4
1980-
4
2000-2099
4
Revolution, 1775-1783
4
1732-1799
3
1735-1826
3
1751-1836
3
1757-1804
3
1775-1783
3
1783-1809
3
1783-1815
3
1819-1892
3
1865-1898
3
1865-1918
3
1913-1994
3
1918-
3
1961-1969
3
2017-2021
3
2020
3
To 1865
3
1800-1899
2
1815-1861
2
1817-1862
2
1819-1891
2
1861-1865
2
1864-1946
2
1917-1963
2
1919-1933
2
1921-1923
2
1923-1929
2
1925-1968
2
1929-1968
2
1932-2009
2
more ...