| Year | Value | | 2021 | 74.8623274 | | 2020 | 70.48342785 | | 2019 | 67.85071029 | | 2017 | 60.18230126 | | 2011 | 49.6 | | 2009 | 54.21 | | 2008 | 54.52 | | 2007 | 50.36482211 | | 2006 | 50.20865936 | | 2005 | 50.2595642 | | 2004 | 50.56634304 | | 2003 | 50.00345304 | | 2002 | 50.83483994 | | 2001 | 50.34166909 | | 2000 | 48.79949531 | | 1999 | 42.80331575 | | 1998 | 1.408557941 | | 1997 | 1.41854848 | | 1996 | 1.428075186 | | 1995 | 1.362132711 |
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