| Year | Value | | 2023 | 71.401492494102 | | 2022 | 70.698367917568 | | 2021 | 69.909653525329 | | 2020 | 69.834587569356 | | 2019 | 68.463788423982 | | 2018 | 67.991742804027 | | 2017 | 67.266111539431 | | 2016 | 67.554802406637 | | 2015 | 66.883888217118 | | 2014 | 66.063577257121 | | 2013 | 64.076303743376 | | 2012 | 62.932981481091 | | 2011 | 61.7112574615 | | 2010 | 60.899356238626 | | 2009 | 60.02780296811 | | 2008 | 60.99248788712 | | 2007 | 60.462079039075 | | 2006 | 58.905061940653 | | 2005 | 56.737639800155 | | 2004 | 54.470440485467 | | 2003 | 50.632509767757 | | 2002 | 49.755686273488 | | 2001 | 47.179996331501 | | 2000 | 48.597508569209 | | 1999 | 47.700757601182 | | 1998 | 48.178620243245 | | 1997 | 48.015129972136 | | 1996 | 47.733440969528 | | 1995 | 47.543267456468 | | 1994 | 47.462112668233 | | 1993 | 47.164316971793 | | 1992 | 46.9687907053 | | 1991 | 46.843987120342 |
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