Era
20th century
15
21st century
12
2001-2009
7
1989-
5
2017-
5
1945-1989
4
1946-
4
2009-
4
Revolution, 1775-1783
4
1980-
3
1775-1783
2
1815-1861
2
1913-1921
2
1917-1963
2
1961-1963
2
1963-1969
2
1969-1974
2
2001-
2
Civil War, 1861-1865
2
1743-1826
1
1775-1865
1
1783-1865
1
1789-1815
1
17th century
1
1800-1837
1
1801-1809
1
1817-1825
1
1849
1
1849-1861
1
1853-1857
1
1865-1933
1
1890-1969
1
1898-1952
1
18th century
1
1903-1950
1
1933-1945
1
1933-1953
1
1952-1998
1
1953-
1
1953-1961
1
1960
1
1960-1980
1
1971-
1
1975-1985
1
1977-1981
1
1993-2001
1
1997-2007
1
19th century
1
2009-2017
1
2016
1
more ...