| Year | Value | | 2022 | 54.077841369203 | | 2021 | 53.755574872644 | | 2020 | 53.512099477525 | | 2019 | 48.382936875644 | | 2018 | 47.944726012479 | | 2017 | 49.876219208368 | | 2016 | 51.749979815378 | | 2015 | 48.578755174224 | | 2014 | 49.66972461 | | 2013 | 44.490667358104 | | 2012 | 43.109095081621 | | 2011 | 47.100030659502 | | 2010 | 44.568677933309 | | 2009 | 47.341177223093 | | 2008 | 49.469394965158 | | 2007 | 49.236459960705 | | 2006 | 48.000268969343 | | 2005 | 47.696232283933 | | 2004 | 47.693078192011 | | 2003 | 47.506275163154 | | 2002 | 47.190004411626 | | 2001 | 47.103954477779 | | 2000 | 47.120522604672 | | 1999 | 47.07294110384 | | 1998 | 46.951890133303 | | 1997 | 46.90072860615 | | 1996 | 46.929231255977 | | 1995 | 46.956130360955 | | 1994 | 46.942295735868 | | 1993 | 47.038426830005 | | 1992 | 47.06572205931 | | 1991 | 47.071083216395 |
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