Era
20th century
551
1900-1999
135
19th century
121
1945-
80
21st century
53
1970-
43
Since 1900
43
1918-1945
32
1980-
30
1800-1899
29
1971-
25
1945-1989
24
1945-1970
20
2000-2099
20
1800-1999
17
1960-1980
15
1989-
15
1933-1945
12
1783-1865
11
1865-1918
11
1900 - 1999
11
1980-2020
11
Civil War, 1861-1865
10
1961-1969
9
Since 1970
9
18th century
8
1935-1977
8
1981-1989
8
1900-2099
7
1919-1933
7
1918-1932
6
1939-1945
6
2001-2009
6
1835-1910
5
1917-1963
5
1929
5
1969-
5
1969-1974
5
1564-1616
4
1810-1891
4
1815-1861
4
1928-1987
4
1953-1961
4
1960-
4
1975-
4
1993-2001
4
Revolution, 1775-1783
4
Since 1945
4
1700-1899
3
1800 - 1899
3
more ...