Era
20th century
493
1945-
281
1970-
182
19th century
164
1865-1918
105
1783-1865
101
1918-1945
99
1900-1999
79
21st century
79
To 1783
76
Since 1900
60
18th century
56
Colonial period, ca. 1600-1775
49
1980-
47
Civil War, 1861-1865
40
1989-
34
2000-2099
34
Revolution, 1775-1783
31
Since 1970
31
Since 1945
30
1800-1899
29
1945-1989
29
1960-1980
22
17th century
21
To 1865
19
1933-1945
18
1815-1861
16
1861-1865
15
1961-1969
15
1945-1970
13
1950-
13
1929
12
1971-
10
1783-1850
9
1981-1989
9
1700-1799
8
1819-1892
8
1838-1918
8
1900-2099
8
1945-1953
8
1564-1616
7
1743-1826
7
1800-1999
7
1882-1945
7
1918-1932
7
1919-1933
7
1969-1974
7
1775-1865
6
1803-1882
6
1805-1859
6
more ...