| Year | Value | | 2023 | 49.314242025496 | | 2022 | 48.982761381224 | | 2021 | 48.770607897569 | | 2020 | 48.506123495345 | | 2019 | 48.636376617072 | | 2018 | 48.238063409956 | | 2017 | 47.84092454917 | | 2016 | 47.448936554799 | | 2015 | 47.177136528641 | | 2014 | 46.792417240404 | | 2013 | 46.546313350747 | | 2012 | 46.163378508625 | | 2011 | 46.036315323295 | | 2010 | 45.807248764415 | | 2009 | 45.577128256963 | | 2008 | 45.508281863114 | | 2007 | 45.19789383889 | | 2006 | 44.923271920692 | | 2005 | 44.882369734801 | | 2004 | 44.724540377737 | | 2003 | 44.66204367926 | | 2002 | 44.590785420735 | | 2001 | 44.553836272828 | | 2000 | 44.592228079085 | | 1999 | 44.649419707267 | | 1998 | 44.765387421014 | | 1997 | 44.823883802082 | | 1996 | 44.887687575729 | | 1995 | 44.995418415837 | | 1994 | 45.056281342143 | | 1993 | 45.305881193971 | | 1992 | 45.431204389282 | | 1991 | 45.666427728116 |
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