| Year | Value | | 2022 | 58.663898169724 | | 2021 | 58.048893270353 | | 2020 | 57.894303139716 | | 2019 | 58.100495008739 | | 2018 | 57.57013745952 | | 2017 | 56.994099652378 | | 2016 | 56.58735253546 | | 2015 | 56.167493226326 | | 2014 | 55.7252768065 | | 2013 | 54.999290743097 | | 2012 | 54.554509336172 | | 2011 | 53.780705255287 | | 2010 | 53.1279149589 | | 2009 | 52.452773743309 | | 2008 | 51.7973643392 | | 2007 | 50.84614499503 | | 2006 | 49.853112233544 | | 2005 | 48.979306207041 | | 2004 | 48.201385122835 | | 2003 | 47.159780321199 | | 2002 | 46.484551732256 | | 2001 | 45.852907396202 | | 2000 | 45.13792981805 | | 1999 | 44.604331954378 | | 1998 | 44.116196745265 | | 1997 | 43.706131873389 | | 1996 | 43.42763097385 | | 1995 | 42.842274991188 | | 1994 | 42.369803320864 | | 1993 | 42.085163716193 | | 1992 | 41.702828842569 | | 1991 | 41.423256770059 |
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