Year | Value | 2022 | 27.176176689111 | 2021 | 26.000568667364 | 2020 | 24.494407660523 | 2019 | 25.824697877813 | 2018 | 26.569683900585 | 2017 | 25.854098743938 | 2016 | 24.987993175878 | 2015 | 24.99556133736 | 2014 | 26.077016942203 | 2013 | 26.889753296947 | 2012 | 28.058594012099 | 2011 | 28.694839408657 | 2010 | 28.495663144218 | 2009 | 27.236068244396 | 2008 | 30.090418908996 | 2007 | 29.926972428298 | 2006 | 30.01336742686 | 2005 | 28.231431649847 | 2004 | 26.252316055633 | 2003 | 24.83763904853 | 2002 | 24.217477494357 | 2001 | 23.289384626526 | 2000 | 24.176031563672 | 1999 | 22.562276282177 | 1998 | 22.673776818042 | 1997 | 23.653782632224 | 1996 | 23.613467029929 | 1995 | 22.801253884473 | 1994 | 21.925568002049 | 1993 | 21.274935620917 | 1992 | 19.725228036589 | 1991 | 19.273446741206 | 1990 | 20.443352219099 | 1989 | 20.07250406904 | 1988 | 20.369440585072 | 1987 | 19.994774382615 | 1986 | 19.817848108403 | 1985 | 22.004059274018 | 1984 | 21.317075630234 | 1983 | 22.021285622417 | 1982 | 22.103871173295 | 1981 | 24.210765496859 | 1980 | 24.424133204532 | 1979 | 23.728319828403 | 1978 | 22.755087212288 | 1977 | 25.404831131355 |
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