Era
1974-
24
20th century
24
21st century
10
1946-1974
6
1930-1946
2
19th century
2
Republic, 1931-1939
2
1758-1794
1
1898?-1948
1
18th century
1
1918-1945
1
1939-1975
1
1943-
1
1945-1983
1
1951-1979
1
1952-
1
1965–2004
1
1970-
1
1973-1988
1
1975-1982
1
1979-
1
1981-
1
1983-
1
1983-2002
1
1988-
1
2000-
1
Civil War, 1936-1939
1
Revolution, 1789-1799
1