| Year | Value | | 2021 | 89.748556749413 | | 2020 | 89.820723724836 | | 2019 | 89.892824502902 | | 2018 | 89.965024082994 | | 2017 | 90.03712486106 | | 2016 | 90.09704828949 | | 2015 | 90.166975422996 | | 2014 | 90.240405088304 | | 2013 | 90.313834753612 | | 2012 | 90.387264418921 | | 2011 | 90.460694084229 | | 2010 | 90.534123749537 | | 2009 | 90.564018772385 | | 2008 | 90.593913795233 | | 2007 | 90.623808818081 | | 2006 | 90.653703840929 | | 2005 | 90.683598863777 | | 2004 | 90.713493886625 | | 2003 | 90.743388909473 | | 2002 | 90.773283932321 | | 2001 | 90.803178955169 | | 2000 | 90.833073978017 | | 1999 | 90.88827219958 | | 1998 | 90.943470421144 | | 1997 | 90.998668642707 | | 1996 | 91.053866864271 | | 1995 | 91.109065085834 | | 1994 | 91.164263307398 | | 1993 | 91.219461528961 | | 1992 | 91.274659750525 | | 1991 | 91.329857972088 | | 1990 | 91.385056193652 |
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