Era
19th century
15
Colonial period, ca. 1600-1775
13
1775-1865
10
1951-
7
Civil War, 1861-1865
7
Revolution, 1775-1783
6
1926-1992
5
Since 1951
5
-1845
3
1804-1875
3
1861-1865
3
18th century
3
1956-
3
1971-
3
20th century
3
Since 1971
3
-1850
2
1755-1776
2
1773-1844
2
1777-1861
2
1779-1865
2
1793-1863
2
1817-1825
2
1860-1927
2
1865-1950
2
1896-1940
2
1938-
2
1945-1970
2
21st century
2
To 1775
2
-1830,
1
-1855
1
-1861
1
-1871
1
-1875
1
-1881
1
1640-1719
1
1675-1710
1
1717-1804
1
1724-1806
1
1727-1795
1
1727-1799
1
1729-1796
1
1735-1826
1
1742-1823
1
1743-1804
1
1744-1837
1
1745-1823
1
1750-1810
1
1750-1848
1
more ...