Era
20th century
28
18th century
18
19th century
17
1900-1999
14
Civil War, 1861-1865
12
Colonial period, ca. 1600-1775
9
Revolution, 1775-1783
8
1951-
6
1800-1837
5
1809-1865
5
1869-1934
5
1945-
5
1918-1945
4
1760-1789
3
1898-1946
3
1933-1945
3
Since 1918
3
1699-1777
2
1783-1850
2
1783-1865
2
17th century
2
1892-1984
2
1918-
2
1918-1938
2
1931-1939
2
1934-
2
1939-1945
2
1939-1975
2
1945-1980
2
1945-1991
2
1973-
2
1975-
2
1976
2
1980-
2
1993-
2
Early 19th century
2
Since 1931
2
Since 1934
2
Since 1945
2
War of 1812
2
-1813
1
1473-1543
1
1489-1561
1
1590-1679
1
1600-1699
1
1656-1680
1
1667?-1708
1
1706-1790
1
1714-1837
1
1723-1791
1
more ...