| Year | Value | | 2023 | 1,452 | | 2022 | 1,430 | | 2021 | 1,410 | | 2020 | 1,387 | | 2019 | 1,358 | | 2018 | 1,344 | | 2017 | 1,325 | | 2016 | 1,304 | | 2015 | 1,289 | | 2014 | 1,259 | | 2013 | 1,227 | | 2012 | 1,222 | | 2011 | 1,241 | | 2010 | 1,266 | | 2009 | 1,267 | | 2008 | 1,240 | | 2007 | 1,207 | | 2006 | 1,191 | | 2005 | 1,199 | | 2004 | 1,224 | | 2003 | 1,261 | | 2002 | 1,292 | | 2001 | 1,301 | | 2000 | 1,293 | | 1999 | 1,276 | | 1998 | 1,255 | | 1997 | 1,247 | | 1996 | 1,250 | | 1995 | 1,252 | | 1994 | 1,252 | | 1993 | 1,249 | | 1992 | 1,237 | | 1991 | 1,208 | | 1990 | 1,171 | | 1989 | 1,129 | | 1988 | 1,087 | | 1987 | 1,058 | | 1986 | 1,060 | | 1985 | 1,080 | | 1984 | 1,089 | | 1983 | 1,082 | | 1982 | 1,058 | | 1981 | 1,020 | | 1980 | 978 | | 1979 | 936 | | 1978 | 895 | | 1977 | 859 | | 1976 | 834 | | 1975 | 813 |
|