Era
1775-1783
16
1789-1809
12
1861-1865
12
1797-1801
10
1801-1809
10
1933-1945
10
1945-1953
10
1809-1817
7
1812-1815
7
1918-1945
7
To 1775
7
1783-1809
6
1789-1797
6
20th century
6
War of 1812
6
1783-1865
5
1815-1861
5
Civil War, 1861-1865
5
Revolution, 1775-1783
5
1783-1789
4
1801-1815
4
1789-1815
3
1848-1871
3
1882-1945
3
18th century
3
1913-1921
3
1979-
3
Since 1979
3
(1860-1941)
2
(1881-1943)
2
1732-1799
2
1745-1829
2
1751-1836
2
1755-1795
2
1770-1814
2
1779-1851
2
1790-1800
2
1809-1812
2
1821-1861
2
1848-1852
2
1860-1941
2
1861-1865 (Guerre de Sécession)
2
1871-1918
2
1881-1943
2
1900-1945
2
1917-
2
1952-
2
19th century
2
1706-1790
1
1740-1792
1
more ...