Year | Value | 2021 | 624 | 2020 | 1,502 | 2019 | 1,578 | 2018 | 1,931 | 2012 | 8,625 | 2011 | 12,231 | 2010 | 9,351 | 2001 | 276 | 2000 | 418 | 1999 | 500 | 1998 | 3,600 | 1997 | 3,600 | 1996 | 3,600 | 1995 | 3,500 | 1994 | 3,300 | 1993 | 3,300 | 1992 | 3,300 | 1991 | 3,300 | 1990 | 3,800 | 1989 | 3,800 | 1988 | 4,300 | 1987 | 4,500 | 1986 | 4,500 | 1985 | 6,700 | 1984 | 6,700 | 1983 | 7,000 | 1982 | 7,100 | 1981 | 6,400 | 1980 | 5,200 | 1979 | 5,200 | 1978 | 5,200 | 1977 | 5,200 | 1976 | 5,000 | 1975 | 4,500 | 1974 | 4,400 | 1973 | 4,300 | 1972 | 4,200 | 1971 | 4,200 | 1970 | 4,000 |
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