| Year | Value | | 2022 | 79.180633915402 | | 2021 | 62.995813266862 | | 2020 | 72.476552197599 | | 2019 | 35.150267692446 | | 2018 | 33.277893371221 | | 2017 | 34.274607362858 | | 2016 | 37.05431476589 | | 2015 | 36.1476530964 | | 2014 | 27.556349141194 | | 2013 | 26.041740034342 | | 2012 | 27.521154514895 | | 2011 | 28.437438650411 | | 2010 | 31.847325406974 | | 2009 | 38.029623527091 | | 2008 | 36.813548467436 | | 2007 | 36.358237560821 | | 2006 | 38.175340716218 | | 2005 | 42.061284196479 | | 2004 | 43.292497247663 | | 2003 | 51.430903895868 | | 2002 | 55.96588990206 | | 2001 | 58.333938162288 | | 2000 | 58.857069285806 | | 1999 | 64.024996177954 | | 1998 | 60.523986872672 | | 1997 | 56.719173237177 | | 1996 | 54.701437716445 | | 1995 | 51.068718606391 | | 1994 | 51.306753717232 | | 1993 | 50.273587204537 | | 1992 | 50.912478623752 | | 1991 | 57.634879554051 | | 1990 | 56.347926267281 | | 1989 | 57.749459447026 | | 1988 | 58.224202575667 | | 1987 | 56.660927236783 | | 1986 | 63.020281827808 | | 1985 | 63.671408903167 | | 1984 | 60.547657666253 | | 1983 | 64.881163533168 | | 1982 | 66.990018276395 |
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