| Year | Value | | 2022 | 15,678 | | 2021 | 15,910 | | 2020 | 16,171 | | 2019 | 16,056 | | 2018 | 15,333 | | 2017 | 14,180 | | 2016 | 13,029 | | 2015 | 12,199 | | 2014 | 11,697 | | 2013 | 11,383 | | 2012 | 11,270 | | 2011 | 11,577 | | 2010 | 12,086 | | 2009 | 12,790 | | 2008 | 13,108 | | 2007 | 12,445 | | 2006 | 11,521 | | 2005 | 10,851 | | 2004 | 10,457 | | 2003 | 10,507 | | 2002 | 10,804 | | 2001 | 10,909 | | 2000 | 10,685 | | 1999 | 10,436 | | 1998 | 10,184 | | 1997 | 9,885 | | 1996 | 9,857 | | 1995 | 10,183 | | 1994 | 10,565 | | 1993 | 10,837 | | 1992 | 11,033 | | 1991 | 11,021 | | 1990 | 11,000 | | 1989 | 11,131 | | 1988 | 11,040 | | 1987 | 10,841 | | 1986 | 10,814 | | 1985 | 10,752 | | 1984 | 10,569 | | 1983 | 10,413 | | 1982 | 10,208 | | 1981 | 9,865 | | 1980 | 9,656 | | 1979 | 9,544 | | 1978 | 9,315 | | 1977 | 9,115 | | 1976 | 9,027 | | 1975 | 8,822 | | 1974 | 8,472 | | 1973 | 8,143 | | 1972 | 7,776 | | 1971 | 7,342 | | 1970 | 6,922 | | 1969 | 6,562 | | 1968 | 6,254 | | 1967 | 5,984 | | 1966 | 5,822 | | 1965 | 5,795 | | 1964 | 5,816 | | 1963 | 5,827 | | 1962 | 5,875 | | 1961 | 5,986 | | 1960 | 6,145 |
|