| Year | Value | | 2022 | 61.095484484742 | | 2021 | 60.923879059259 | | 2020 | 60.844980276223 | | 2019 | 60.945367693211 | | 2018 | 60.939239475529 | | 2017 | 60.566186066462 | | 2016 | 60.587896875811 | | 2015 | 60.703687720203 | | 2014 | 60.392966548382 | | 2013 | 59.934741822335 | | 2012 | 59.921599788828 | | 2011 | 59.892135979531 | | 2010 | 59.499009574117 | | 2009 | 59.38095113331 | | 2008 | 59.809739667643 | | 2007 | 59.511285980534 | | 2006 | 59.307394051438 | | 2005 | 58.959685720309 | | 2004 | 58.796546437417 | | 2003 | 58.700535377792 | | 2002 | 58.678636170735 | | 2001 | 58.505245323056 | | 2000 | 58.219486339716 | | 1999 | 57.939623626389 | | 1998 | 57.773610590972 | | 1997 | 57.679680108288 | | 1996 | 57.770143302424 | | 1995 | 57.653445850116 | | 1994 | 57.635970635746 | | 1993 | 57.612647575473 | | 1992 | 57.547719979633 | | 1991 | 57.457606941416 |
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