Era
20th century
77
21st century
28
19th century
26
1945-
9
1945-1989
9
1989-
8
2001-2009
8
Revolution, 1775-1783
6
18th century
5
1980-
5
2017-
5
1865-1918
4
1946-
4
1960-1980
4
2001-
4
Colonial period, ca. 1600-1775
4
1783-1850
3
1789-1900
3
1882-1945
3
1885-1972
3
1888-1965
3
1918-1945
3
1933-1945
3
1951-
3
1970-
3
2009-
3
2009-2017
3
2016
3
Civil War, 1861-1865
3
1783-1865
2
1860-1935
2
1869-1948
2
1899-1961
2
1929-2007
2
1930-
2
1945-1953
2
1955-2011
2
1960-
2
1969-
2
1971-
2
1975-
2
1981-1993
2
1989-1993
2
Revolutionary period, 1775-1783
2
( 1946 - )
1
1588-1679
1
1603-1714
1
1623-1687
1
1706 - 1790
1
1706-1790
1
more ...