| Year | Value | | 2022 | 78.45797574445 | | 2021 | 78.168180721442 | | 2020 | 77.481225437084 | | 2019 | 77.260392161872 | | 2018 | 77.089623122825 | | 2017 | 76.569822505864 | | 2016 | 76.065002099406 | | 2015 | 75.620514705587 | | 2014 | 75.320358455203 | | 2013 | 75.178807180097 | | 2012 | 75.093805164687 | | 2011 | 74.96242417553 | | 2010 | 74.724678932682 | | 2009 | 75.029642570078 | | 2008 | 74.548378330982 | | 2007 | 73.873847376383 | | 2006 | 73.593264138352 | | 2005 | 73.309578418704 | | 2004 | 72.069537103891 | | 2003 | 71.479515932635 | | 2002 | 71.802618815833 | | 2001 | 72.121634761797 | | 2000 | 71.838470782972 | | 1999 | 71.702252735274 | | 1998 | 71.304356241186 | | 1997 | 71.176030525871 | | 1996 | 70.949045484717 | | 1995 | 70.918865788342 | | 1994 | 71.373005564747 | | 1993 | 71.471017922888 | | 1992 | 71.128481144874 | | 1991 | 71.620909380633 |
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