Yearly event density with release/catalog-offering overlays and catalog-issue counts.
| Year | Total Events | Release | Catalog Offering | Catalog Issues | Density |
|---|---|---|---|---|---|
| 1812 | 1 | 0 | 0 | 0 | |
| 1835 | 1 | 0 | 0 | 0 | |
| 1844 | 3 | 0 | 0 | 0 | |
| 1855 | 2 | 0 | 0 | 0 | |
| 1869 | 3 | 0 | 0 | 0 | |
| 1870 | 1 | 0 | 0 | 0 | |
| 1872 | 1 | 0 | 0 | 0 | |
| 1878 | 1 | 0 | 0 | 0 | |
| 1884 | 1 | 0 | 0 | 0 | |
| 1885 | 3 | 1 | 0 | 0 | |
| 1886 | 4 | 0 | 0 | 0 | |
| 1888 | 2 | 0 | 0 | 0 | |
| 1890 | 1 | 0 | 0 | 0 | |
| 1894 | 2 | 0 | 0 | 0 | |
| 1895 | 6 | 0 | 0 | 0 | |
| 1896 | 1 | 0 | 0 | 0 | |
| 1897 | 9 | 0 | 0 | 0 | |
| 1898 | 2 | 0 | 0 | 0 | |
| 1899 | 1 | 0 | 0 | 0 | |
| 1901 | 2 | 0 | 0 | 0 | |
| 1902 | 7 | 0 | 0 | 0 | |
| 1903 | 2 | 0 | 0 | 0 | |
| 1904 | 13 | 0 | 0 | 0 | |
| 1905 | 7 | 0 | 0 | 0 | |
| 1906 | 3 | 0 | 0 | 0 | |
| 1907 | 14 | 1 | 0 | 0 | |
| 1908 | 10 | 0 | 0 | 0 | |
| 1909 | 1 | 0 | 0 | 0 | |
| 1910 | 2 | 0 | 0 | 0 | |
| 1911 | 26 | 0 | 0 | 0 | |
| 1912 | 5 | 1 | 0 | 0 | |
| 1913 | 2 | 0 | 0 | 0 | |
| 1915 | 11 | 0 | 0 | 0 | |
| 1918 | 2 | 0 | 0 | 0 | |
| 1920 | 5 | 0 | 0 | 0 | |
| 1922 | 1 | 0 | 0 | 0 | |
| 1923 | 6 | 1 | 0 | 0 | |
| 1924 | 1 | 0 | 0 | 0 | |
| 1925 | 5 | 0 | 0 | 0 | |
| 1926 | 1 | 0 | 0 | 0 | |
| 1927 | 12 | 1 | 0 | 0 | |
| 1928 | 1 | 0 | 0 | 0 | |
| 1930 | 6 | 1 | 0 | 0 | |
| 1932 | 4 | 1 | 0 | 0 | |
| 1934 | 5 | 1 | 0 | 0 | |
| 1935 | 1 | 0 | 0 | 0 | |
| 1936 | 10 | 1 | 0 | 0 | |
| 1937 | 2 | 0 | 0 | 0 | |
| 1938 | 2 | 0 | 0 | 0 | |
| 1939 | 1 | 0 | 0 | 0 | |
| 1940 | 28 | 2 | 0 | 0 | |
| 1941 | 9 | 0 | 0 | 0 | |
| 1942 | 3 | 1 | 0 | 0 | |
| 1943 | 11 | 0 | 0 | 0 | |
| 1944 | 11 | 0 | 0 | 0 | |
| 1945 | 17 | 0 | 0 | 0 | |
| 1946 | 19 | 0 | 0 | 0 | |
| 1950 | 3 | 0 | 0 | 0 | |
| 1952 | 5 | 1 | 0 | 0 | |
| 1953 | 1 | 0 | 0 | 0 | |
| 1954 | 1 | 0 | 0 | 0 | |
| 1955 | 5 | 1 | 0 | 0 | |
| 1956 | 2 | 0 | 0 | 0 | |
| 1957 | 5 | 0 | 0 | 0 | |
| 1958 | 3 | 0 | 0 | 0 | |
| 1959 | 19 | 1 | 0 | 0 | |
| 1960 | 35 | 1 | 0 | 0 | |
| 1961 | 1 | 0 | 0 | 0 | |
| 1962 | 2 | 0 | 0 | 0 | |
| 1963 | 1 | 0 | 0 | 0 | |
| 1964 | 9 | 0 | 0 | 0 | |
| 1966 | 1 | 0 | 0 | 0 | |
| 1967 | 5 | 0 | 0 | 0 | |
| 1968 | 2 | 0 | 0 | 0 | |
| 1972 | 1 | 0 | 0 | 0 | |
| 1973 | 4 | 1 | 0 | 0 | |
| 1974 | 4 | 0 | 0 | 0 | |
| 1975 | 14 | 2 | 0 | 0 | |
| 1976 | 16 | 1 | 0 | 0 | |
| 1978 | 1 | 0 | 0 | 0 | |
| 1979 | 18 | 3 | 0 | 0 | |
| 1980 | 9 | 1 | 0 | 0 | |
| 1981 | 4 | 0 | 0 | 0 | |
| 1982 | 2 | 0 | 0 | 0 | |
| 1984 | 1 | 0 | 0 | 0 | |
| 1985 | 14 | 0 | 0 | 0 | |
| 1986 | 16 | 2 | 0 | 0 | |
| 1987 | 1 | 0 | 0 | 0 | |
| 1988 | 1 | 0 | 0 | 0 | |
| 1989 | 2 | 0 | 0 | 0 | |
| 1990 | 17 | 1 | 0 | 0 | |
| 1991 | 16 | 0 | 0 | 0 | |
| 1993 | 3 | 0 | 0 | 0 | |
| 1994 | 1 | 0 | 0 | 0 | |
| 1996 | 2 | 0 | 0 | 0 | |
| 1997 | 2 | 0 | 0 | 0 | |
| 1998 | 1 | 0 | 0 | 0 | |
| 1999 | 27 | 2 | 0 | 0 | |
| 2001 | 4 | 0 | 0 | 0 | |
| 2002 | 5 | 0 | 0 | 0 | |
| 2003 | 5 | 0 | 0 | 0 | |
| 2004 | 2 | 0 | 0 | 0 | |
| 2006 | 1 | 0 | 0 | 0 | |
| 2007 | 2 | 0 | 0 | 0 | |
| 2008 | 4 | 1 | 0 | 0 | |
| 2009 | 1 | 0 | 0 | 0 | |
| 2010 | 4 | 0 | 0 | 0 | |
| 2011 | 1 | 0 | 0 | 0 | |
| 2012 | 1 | 0 | 0 | 0 | |
| 2013 | 1 | 0 | 0 | 0 | |
| 2014 | 1 | 0 | 0 | 0 | |
| 2015 | 2 | 1 | 0 | 0 | |
| 2016 | 6 | 0 | 0 | 0 | |
| 2017 | 1 | 0 | 0 | 0 | |
| 2019 | 1 | 0 | 0 | 0 |