| Year | Value | | 2022 | 88.500776322599 | | 2021 | 91.211838069509 | | 2020 | 92.034903351059 | | 2019 | 83.729943270113 | | 2018 | 86.552517000147 | | 2017 | 88.788734651363 | | 2016 | 91.336485454133 | | 2015 | 90.258766370934 | | 2014 | 91.253504970686 | | 2013 | 90.494178911761 | | 2012 | 91.326115933548 | | 2011 | 90.170517996736 | | 2010 | 90.011365768072 | | 2009 | 87.2948158101 | | 2008 | 84.890026644376 | | 2007 | 82.179075738126 | | 2006 | 85.248194999348 | | 2005 | 90.22777850504 | | 2004 | 89.397590361446 | | 2003 | 86.250194734382 | | 2002 | 88.665700949622 | | 2001 | 90.008184645605 | | 2000 | 87.962085308057 | | 1999 | 87.279770928078 | | 1998 | 86.127779738793 | | 1997 | 88.587064676617 | | 1996 | 87.149768615902 | | 1995 | 88.118412200045 | | 1994 | 82.537554887913 | | 1993 | 84.73734939759 | | 1992 | 85.401124169647 | | 1991 | 85.322342519685 | | 1990 | 83.822584630591 | | 1989 | 67.216852540273 | | 1988 | 67.216127262754 | | 1987 | 71.321470245041 | | 1986 | 71.217475104401 | | 1985 | 65.372134038801 | | 1984 | 67.168696936139 | | 1983 | 67.063555913113 | | 1982 | 68.005126014524 | | 1981 | 69.455600178492 | | 1980 | 65.785854616896 | | 1979 | 87.191277905511 | | 1978 | 87.396482961111 | | 1977 | 87.50042775388 | | 1976 | 91.297214930181 | | 1975 | 90.799085718225 |
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