| Year | Value | | 2022 | 80.117541418937 | | 2021 | 79.357370654428 | | 2020 | 79.771874345285 | | 2019 | 79.813922725308 | | 2018 | 80.037236515058 | | 2017 | 78.552445416657 | | 2016 | 77.319042637549 | | 2015 | 75.300500909699 | | 2014 | 75.445583070355 | | 2013 | 75.634405731829 | | 2012 | 78.456326545986 | | 2011 | 77.930777977576 | | 2010 | 79.482740656143 | | 2009 | 79.229372168929 | | 2008 | 79.770952065688 | | 2007 | 82.74647978311 | | 2006 | 84.674203078166 | | 2005 | 87.359422774513 | | 2004 | 84.922041634193 | | 2003 | 84.558737708267 | | 2002 | 83.511490988136 | | 2001 | 84.960652995023 | | 2000 | 85.673975648269 | | 1999 | 89.000732861206 | | 1998 | 89.424903466035 | | 1997 | 85.512213677593 | | 1996 | 84.771288319854 | | 1995 | 81.714976480172 | | 1994 | 77.255229265051 | | 1993 | 76.043382345601 | | 1992 | 77.001923970013 | | 1991 | 75.88819819411 | | 1990 | 79.205035551929 |
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