Year | Value | 2022 | 23.138157486576 | 2021 | 23.51157087994 | 2020 | 22.498164916174 | 2019 | 23.170599230094 | 2018 | 22.920077957088 | 2017 | 22.723404744582 | 2016 | 22.118721635368 | 2015 | 22.480504680704 | 2014 | 22.036636860826 | 2013 | 21.324372411628 | 2012 | 21.24242136689 | 2011 | 20.694576669869 | 2010 | 20.102486785791 | 2009 | 19.106332598139 | 2008 | 20.79935124393 | 2007 | 22.385751870918 | 2006 | 22.890574818699 | 2005 | 22.113389568041 | 2004 | 21.834420435938 | 2003 | 21.210805958878 | 2002 | 21.628627302142 | 2001 | 22.373858241911 | 2000 | 23.124526792733 | 1999 | 23.011955116147 | 1998 | 23.600497899568 | 1997 | 23.196696494275 | 1996 | 22.521386836491 | 1995 | 20.9186824365 | 1994 | 19.862794702718 | 1993 | 19.086728056444 | 1992 | 19.352821096885 | 1991 | 20.420466453744 | 1990 | 21.081413755385 | 1989 | 21.79343641381 | 1988 | 22.180756102868 | 1987 | 21.31502185109 | 1986 | 21.047953589642 | 1985 | 21.523679527202 | 1984 | 22.071565153688 | 1983 | 20.765947775447 | 1982 | 21.357227064909 | 1981 | 22.314745174627 | 1980 | 22.419645890327 | 1979 | 23.580492139452 | 1978 | 23.612838562366 | 1977 | 22.803329172772 | 1976 | 22.499003250181 | 1975 | 21.890237657152 |
|