Era
20th century
248
21st century
107
19th century
74
2009-
68
1876-1950
45
1991-
38
1951-
32
Quaternary
32
18th century
31
Cretaceous
30
2001-2009
27
To 1500
27
1564-1616
24
1989-
24
2001-
24
2003-
21
1945-
20
2000-
20
Civil War, 1861-1865
20
1956-
19
17th century
17
1889-1951
17
1990-
17
1993-
17
16th century
16
Civil War, 2011-
15
1954-
14
Tertiary
14
1952-
12
1980-
12
1946-
11
1947-
11
1957-
11
1965-
11
1882-1941
10
1942-
10
1944-
10
1949-
10
1958-
10
1960-
10
1964-
10
1986-
10
Holocene
10
Revolution, 1775-1783
10
1724-1804
9
1948-
9
1959-
9
1988-
9
1991-2003
9
1938-1988
8
more ...