Era
20th century
24
19th century
8
18th century
6
1945-
5
1918-1945
2
1933-1945
2
1965-1975
2
1970-
2
1980-
2
21st century
2
17th century
1
1801-1917
1
1861-1917
1
1868-1963
1
1917-1945
1
1917-1970
1
1918-1933
1
1945-1989
1
1947-
1
1955-1965
1
1975-1985
1
1976-
1
1985-
1
1990-
1
1991-
1
Revolution, 1775-1783
1