| Year | Value | | 2022 | 27,313 | | 2021 | 28,280 | | 2020 | 28,927 | | 2019 | 29,325 | | 2018 | 29,735 | | 2017 | 30,076 | | 2016 | 30,334 | | 2015 | 30,491 | | 2014 | 30,387 | | 2013 | 29,889 | | 2012 | 29,102 | | 2011 | 27,680 | | 2010 | 25,411 | | 2009 | 22,931 | | 2008 | 20,637 | | 2007 | 18,558 | | 2006 | 16,870 | | 2005 | 15,738 | | 2004 | 15,053 | | 2003 | 14,652 | | 2002 | 14,367 | | 2001 | 14,198 | | 2000 | 14,207 | | 1999 | 14,155 | | 1998 | 13,930 | | 1997 | 13,678 | | 1996 | 13,494 | | 1995 | 13,517 | | 1994 | 13,997 | | 1993 | 15,099 | | 1992 | 16,513 | | 1991 | 17,764 | | 1990 | 18,687 | | 1989 | 19,296 | | 1988 | 19,589 | | 1987 | 19,637 | | 1986 | 19,541 | | 1985 | 19,256 | | 1984 | 18,672 | | 1983 | 17,798 | | 1982 | 16,808 | | 1981 | 15,914 | | 1980 | 15,388 | | 1979 | 15,027 | | 1978 | 14,437 | | 1977 | 13,594 | | 1976 | 12,502 | | 1975 | 11,210 | | 1974 | 9,798 | | 1973 | 8,365 | | 1972 | 7,021 | | 1971 | 5,888 | | 1970 | 5,156 | | 1969 | 4,829 | | 1968 | 4,769 | | 1967 | 4,876 | | 1966 | 5,062 | | 1965 | 5,255 | | 1964 | 5,357 | | 1963 | 5,385 | | 1962 | 5,406 | | 1961 | 5,342 | | 1960 | 5,550 |
|