| Year | Value | | 2022 | 3,628 | | 2021 | 3,608 | | 2020 | 3,528 | | 2019 | 3,433 | | 2018 | 3,344 | | 2017 | 3,291 | | 2016 | 3,288 | | 2015 | 3,345 | | 2014 | 3,455 | | 2013 | 3,590 | | 2012 | 3,715 | | 2011 | 3,790 | | 2010 | 3,729 | | 2009 | 3,562 | | 2008 | 3,414 | | 2007 | 3,314 | | 2006 | 3,271 | | 2005 | 3,267 | | 2004 | 3,250 | | 2003 | 3,213 | | 2002 | 3,180 | | 2001 | 3,161 | | 2000 | 3,115 | | 1999 | 3,066 | | 1998 | 3,047 | | 1997 | 3,005 | | 1996 | 2,942 | | 1995 | 2,870 | | 1994 | 2,776 | | 1993 | 2,667 | | 1992 | 2,576 | | 1991 | 2,317 | | 1990 | 1,990 | | 1989 | 1,879 | | 1988 | 1,945 | | 1987 | 2,104 | | 1986 | 2,279 | | 1985 | 2,454 | | 1984 | 2,631 | | 1983 | 2,807 | | 1982 | 2,988 | | 1981 | 3,217 | | 1980 | 3,442 | | 1979 | 3,601 | | 1978 | 3,733 | | 1977 | 3,839 | | 1976 | 3,899 | | 1975 | 3,879 | | 1974 | 3,783 | | 1973 | 3,671 | | 1972 | 3,548 | | 1971 | 3,443 | | 1970 | 3,387 | | 1969 | 3,362 | | 1968 | 3,349 | | 1967 | 3,311 | | 1966 | 3,205 | | 1965 | 3,073 | | 1964 | 2,969 | | 1963 | 2,881 | | 1962 | 2,806 | | 1961 | 2,739 | | 1960 | 2,643 |
|