| Year | Value | | 2019 | 66.557998657227 | | 2018 | 66.38200378418 | | 2017 | 66.207000732422 | | 2016 | 68.599998474121 | | 2015 | 70.338996887207 | | 2014 | 69.811996459961 | | 2013 | 69.11499786377 | | 2012 | 68.420997619629 | | 2011 | 67.789001464844 | | 2010 | 67.004997253418 | | 2009 | 66.222999572754 | | 2008 | 65.310997009277 | | 2007 | 64.032997131348 | | 2006 | 62.70000076294 | | 2005 | 61.464000701904 | | 2004 | 60.096000671387 | | 2003 | 58.382999420166 | | 2002 | 56.585998535156 | | 2001 | 54.888000488281 | | 2000 | 53.244998931885 | | 1999 | 52.50899887085 | | 1998 | 52.076000213623 | | 1997 | 51.45000076294 | | 1996 | 50.921001434326 | | 1995 | 50.20299911499 | | 1994 | 49.587001800537 | | 1993 | 48.845001220703 | | 1992 | 48.548999786377 | | 1991 | 47.896999359131 |
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