Year | Value | 2022 | 17.406675885939 | 2021 | 19.080530256043 | 2020 | 19.606820442586 | 2019 | 19.421016659194 | 2018 | 18.735866111271 | 2017 | 20.820558598824 | 2016 | 22.135548403963 | 2015 | 24.713472345907 | 2014 | 24.712339151954 | 2013 | 24.333747087338 | 2012 | 21.834141482676 | 2011 | 22.879893385984 | 2010 | 21.817616143418 | 2009 | 22.525164399932 | 2008 | 21.811006694423 | 2007 | 17.799149985404 | 2006 | 16.991374042844 | 2005 | 14.219255595821 | 2004 | 15.809860107328 | 2003 | 16.322530099897 | 2002 | 18.82139077109 | 2001 | 17.31020594098 | 2000 | 16.005476382134 | 1999 | 11.513666018459 | 1998 | 11.187958922062 | 1997 | 15.20944516296 | 1996 | 15.999911307815 | 1995 | 18.627020629123 | 1994 | 23.256858515363 | 1993 | 24.218367621957 | 1992 | 22.898112519074 | 1991 | 24.919416488951 | 1990 | 20.706560205152 |
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