Year | Value | 2021 | 30,789 | 2020 | 22,125 | 2019 | 58,509 | 2018 | 55,637 | 2017 | 52,063 | 2016 | 46,733 | 2015 | 45,596 | 2014 | 42,249.8 | 2013 | 43,956 | 2012 | 51,685 | 2011 | 57,823 | 2010 | 61,515 | 2009 | 57,893 | 2008 | 55,386 | 2007 | 51,222 | 2006 | 42,754 | 2005 | 38,995 | 2004 | 30,524 | 2003 | 26,844 | 2002 | 17,748 | 2001 | 20,781 | 2000 | 23,298 | 1999 | 17,900 | 1998 | 15,400 | 1997 | 25,600 | 1996 | 17,100 | 1995 | 22,200 | 1994 | 21,300 | 1993 | 18,100 | 1992 | 16,100 | 1991 | 20,200 | 1990 | 22,000 | 1989 | 24,100 | 1988 | 23,000 | 1987 | 23,700 | 1986 | 24,600 | 1985 | 23,000 | 1984 | 22,100 | 1983 | 18,700 | 1982 | 17,100 | 1981 | 12,500 | 1980 | 18,200 | 1979 | 18,100 | 1978 | 17,900 | 1977 | 22,000 | 1976 | 15,900 | 1975 | 13,200 | 1974 | 13,600 | 1973 | 8,400 | 1972 | 6,900 | 1971 | 6,600 | 1970 | 6,600 |
|