*Excludes Observations that spanned multiple years
Pre 1970 | 36 |
---|---|
1970 | 1 |
1971 | 4 |
1972 | 14 |
1973 | 23 |
1974 | 26 |
1975 | 29 |
1976 | 24 |
1977 | 27 |
1978 | 18 |
1979 | 20 |
1980 | 56 |
1981 | 49 |
1982 | 95 |
1983 | 101 |
1984 | 197 |
1985 | 187 |
1986 | 141 |
1987 | 78 |
1988 | 118 |
1989 | 286 |
1990 | 334 |
1991 | 256 |
1992 | 350 |
1993 | 643 |
1994 | 695 |
1995 | 587 |
1996 | 359 |
1997 | 385 |
1998 | 458 |
1999 | 672 |
2000 | 604 |
2001 | 969 |
2002 | 1164 |
2003 | 702 |
2004 | 983 |
2005 | 716 |
2006 | 876 |
2007 | 995 |
2008 | 1062 |
2009 | 1153 |
2010 | 1062 |
2011 | 718 |
2012 | 865 |
2013 | 463 |
2014 | 430 |
2015 | 520 |
2016 | 186 |
2017 | 18 |
2018 | 1 |
2019 | 2 |
2020 | 9 |
2021 | 0 |
Total | 19767 |