Era
20th century
568
1900-1999
178
19th century
162
21st century
104
2000-2099
54
1800-1899
43
1975-
37
1941-1955
32
Civil War, 1861-1865
31
18th century
24
1877-1964
19
1945-1989
19
1800-1999
16
1933-1945
16
1980-
16
1989-
15
1865-1950
13
1861-1865
12
1929-1968
11
1946-
11
1993-
11
To 1964
11
17th century
10
1945-
10
2001-2009
10
1868-1963
9
Since 1900
9
1865-1918
8
1951-
8
Colonial period, ca. 1600-1775
8
Revolution, 1775-1783
8
Since 1975
8
1818-1895
7
1863-1877
7
1775-1865
6
1809-1865
6
1865-1877
6
1900 - 1999
6
1973-2020
6
To 1500
6
1700-1799
5
1783-1865
5
1856-1915
5
1900-2099
5
1979-1997
5
2009-2017
5
Since 1980
5
1800-1859
4
1858-1942
4
1865-
4
more ...