20th century 6,526 View Records 19th century 3,210 View Records 21st century 1,723 View Records 18th century 1,111 View Records Civil War, 1861-1865 989 View Records 1945- 801 View Records Cretaceous 792 View Records 1945-1989 651 View Records 17th century 641 View Records 1933-1945 543 View Records Revolution, 1775-1783 518 View Records 1989- 434 View Records 16th century 433 View Records Tertiary 430 View Records 2009- 408 View Records 1946- 395 View Records 2001-2009 389 View Records Quaternary 363 View Records 1991- 349 View Records Colonial period, ca. 1600-1775 347 View Records To 1500 325 View Records Paleozoic 308 View Records Precambrian 304 View Records Cenozoic 278 View Records 2000- 261 View Records Permian 237 View Records 1918-1945 227 View Records 1993-2001 223 View Records Eocene 223 View Records 1960- 222 View Records 1981-2001 217 View Records 1564-1616 210 View Records Jurassic 206 View Records Miocene 199 View Records Pennsylvanian 199 View Records Mesozoic 196 View Records 1951- 191 View Records 1929 187 View Records Ordovician 178 View Records Pleistocene 171 View Records 1945-1953 168 View Records Mississippian 163 View Records Devonian 160 View Records 1949- 159 View Records 1979- 159 View Records 1980- 155 View Records 1809-1865 154 View Records 1783-1865 148 View Records 1953-1961 148 View Records Triassic 140 View Records 1990- 137 View Records Civil War, 2011- 136 View Records 1981-1989 135 View Records 1882-1945 134 View Records 2001- 133 View Records Early modern, 1500-1700 133 View Records 1947- 129 View Records 1993- 127 View Records To 1775 124 View Records 1775-1865 117 View Records Revolution, 1789-1799 117 View Records 1997- 116 View Records 2003- 116 View Records 1775-1783 115 View Records 1960-1980 112 View Records Cambrian 109 View Records Pliocene 107 View Records 1969-1974 104 View Records Holocene 103 View Records 1980-2020 101 View Records World War, 1939-1945 101 View Records 1969- 100 View Records To 146 B.C. 99 View Records Oligocene 98 View Records 1913-1994 97 View Records 1970- 97 View Records To 1846 97 View Records 1917-1963 96 View Records Proterozoic 96 View Records 1976-2002 94 View Records 1975- 93 View Records 1981-1993 92 View Records 1865-1918 91 View Records 1952- 91 View Records 1988- 91 View Records 2016 91 View Records Carboniferous 91 View Records To 1848 90 View Records War of 1812 90 View Records 1949-1976 89 View Records 1959-1990 87 View Records 1963-1969 87 View Records 1948- 86 View Records 1815-1861 85 View Records 1965- 85 View Records Silurian 85 View Records 2002- 83 View Records 1858-1919 82 View Records 1889-1945 82 View Records 1789-1900 79 View Records