| Year | Value | | 2021 | 13,321 | | 2020 | 8,941 | | 2019 | 15,617 | | 2018 | 11,635 | | 2017 | 21,224 | | 2016 | 21,628 | | 2015 | 20,539 | | 2014 | 16,764 | | 2013 | 16,560 | | 2012 | 14,902 | | 2011 | 10,683 | | 2010 | 5,645.6695671329 | | 2004 | 3,333 | | 2003 | 3,333 | | 2002 | 4,382 | | 2001 | 5,892 | | 2000 | 4,873 | | 1999 | 5,000 | | 1998 | 3,500 | | 1997 | 3,500 | | 1996 | 3,300 | | 1995 | 3,000 | | 1994 | 3,400 | | 1993 | 3,200 | | 1992 | 15,100 | | 1991 | 19,000 | | 1990 | 12,600 | | 1989 | 11,800 | | 1988 | 12,300 | | 1987 | 7,500 | | 1986 | 5,500 | | 1985 | 5,800 | | 1984 | 4,400 | | 1983 | 4,500 | | 1982 | 5,300 | | 1981 | 5,100 | | 1980 | 5,600 | | 1979 | 7,000 | | 1978 | 7,000 | | 1977 | 6,000 | | 1976 | 6,100 | | 1975 | 5,900 | | 1974 | 5,700 | | 1973 | 5,600 | | 1972 | 5,700 | | 1971 | 5,400 | | 1970 | 5,000 |
|