Era
20th century
1,878
21st century
1,094
19th century
879
18th century
381
To 1500
292
17th century
289
Cretaceous
255
16th century
214
2000-
184
1946-
170
Tertiary
157
2009-
156
1945-
142
1991-
137
1989-
126
Precambrian
108
Quaternary
107
Paleozoic
96
Eocene
94
Permian
89
1724-1804
86
1564-1616
85
Cenozoic
84
Civil War, 2011-
78
Miocene
77
1960-
73
Civil War, 1861-1865
71
Jurassic
69
Pleistocene
68
1947-
67
Ordovician
67
1949-
66
Early modern, 1500-1700
66
Devonian
63
Mississippian
62
1970-
60
Mesozoic
60
2016
58
Pennsylvanian
58
1990-
54
1945-1989
52
Triassic
52
1933-1945
50
1959-
48
2001-
46
1997-
45
Holocene
44
1980-
43
1979-
42
1950-
40
more ...