| Year | Value | | 2022 | 3,510 | | 2021 | 3,424 | | 2020 | 3,413 | | 2019 | 3,490 | | 2018 | 3,615 | | 2017 | 3,749 | | 2016 | 3,879 | | 2015 | 3,975 | | 2014 | 4,007 | | 2013 | 4,009 | | 2012 | 4,007 | | 2011 | 4,006 | | 2010 | 4,023 | | 2009 | 4,052 | | 2008 | 4,070 | | 2007 | 4,063 | | 2006 | 4,032 | | 2005 | 3,980 | | 2004 | 3,918 | | 2003 | 3,870 | | 2002 | 3,855 | | 2001 | 3,875 | | 2000 | 3,931 | | 1999 | 4,015 | | 1998 | 4,105 | | 1997 | 4,174 | | 1996 | 4,202 | | 1995 | 4,186 | | 1994 | 4,133 | | 1993 | 4,052 | | 1992 | 3,952 | | 1991 | 3,849 | | 1990 | 3,768 | | 1989 | 3,685 | | 1988 | 3,560 | | 1987 | 3,409 | | 1986 | 3,252 | | 1985 | 3,097 | | 1984 | 2,953 | | 1983 | 2,784 | | 1982 | 2,576 | | 1981 | 2,340 | | 1980 | 2,107 | | 1979 | 1,892 | | 1978 | 1,727 | | 1977 | 1,628 | | 1976 | 1,568 | | 1975 | 1,572 | | 1974 | 1,626 | | 1973 | 1,707 | | 1972 | 1,794 | | 1971 | 1,877 | | 1970 | 1,945 | | 1969 | 2,002 | | 1968 | 2,050 | | 1967 | 2,094 | | 1966 | 2,131 | | 1965 | 2,161 | | 1964 | 2,188 | | 1963 | 2,212 | | 1962 | 2,233 | | 1961 | 2,248 | | 1960 | 2,263 |
|