Year | Value | 2022 | 25.334705402487 | 2021 | 26.646883948251 | 2020 | 24.625720813906 | 2019 | 25.613321001753 | 2018 | 25.227840658245 | 2017 | 24.77964245828 | 2016 | 24.25056543286 | 2015 | 23.885640826385 | 2014 | 23.218061363827 | 2013 | 22.598740265271 | 2012 | 22.314145760233 | 2011 | 22.683228612852 | 2010 | 21.939009763983 | 2009 | 21.315164817627 | 2008 | 23.554725466079 | 2007 | 24.641455494563 | 2006 | 23.937421292501 | 2005 | 23.068316203334 | 2004 | 22.982241767471 | 2003 | 22.212433203792 | 2002 | 22.62443153505 | 2001 | 22.852250858864 | 2000 | 22.903100361069 | 1999 | 22.961341135233 | 1998 | 23.123402082159 | 1997 | 22.847411491992 | 1996 | 22.299955117688 | 1995 | 22.583264598033 | 1994 | 21.534364441571 | 1993 | 21.171303166696 | 1992 | 21.695407825203 | 1991 | 22.518264477194 | 1990 | 23.351060913065 | 1989 | 23.295931615241 | 1988 | 22.927706989091 | 1987 | 21.947068272475 | 1986 | 22.214283193068 | 1985 | 21.256810133093 | 1984 | 21.11724457075 | 1983 | 20.430502486909 | 1982 | 20.11935531497 | 1981 | 20.493638342971 | 1980 | 22.256338876455 | 1979 | 23.260344702516 | 1978 | 23.448479536736 | 1977 | 23.039894211574 | 1976 | 23.34979916778 | 1975 | 23.349331181574 |
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