19th century 5,478
20th century 4,474
Civil War, 1861-1865 1,007
18th century 802
Early works to 1800 721
Revolution, 1775-1783 595
Quaternary 504
To 1800 493
1939-1945 474
17th century 370
21st century 313
Colonial period, ca. 1600-1775 280
16th century 258
From 2 million years ago 242
Cretaceous 221
1861-1865 220
1914-1918 217
1800-1899 214
1990 192
1945- 183
Precambrian 179
Ottoman Empire, 1288-1918 178
1918 176
1900-1999 175
Nineteen tens 164
1912 161
1917 153
Paleozoic 142
1890 140
1900 140
To 70 A.D 135
1889 132
1775-1783 131
1915 128
Cenozoic 127
1901 124
1873 122
1892 121
1854 118
1905 117
1909 114
1891 111
1939 - 1945 109
Tertiary 107
1700-1799 105
1884 105
Qing dynasty, 1644-1912 104
1914 102
1910 99
1897 97
1850 96
To 1500 96
1874 95
1861 - 1865 92
1875 91
1908 89
1856 88
1898 88
1923 88
1877 87
1896 86
1880 85
1855 84
From 570 million to 5 billion years ago 84
1907 83
1728-1779 82
1862 82
1895 82
French and Indian War, 1754-1763 82
From 65 to 140 million years ago 80
1775 - 1783 79
1904 79
1911 78
1863 77
1906 77
1600-1775 76
1930 76
Since 1945 75
1886 74
1902 74
1732-1799 73
2000-2099 72
Mesozoic 71
Ordovician 70
1903 69
1916 69
Devonian 69
1853 68
1920 68
Geschichte 68
Jurassic 66
1885 65
1980 64
1913 63
Pennsylvanian 63
1789-1815 61
1899 61
Permian 61
1777 60
1849 60