| Year | Value | | 2022 | 91.545217159025 | | 2021 | 91.630936141557 | | 2020 | 91.308758959454 | | 2019 | 91.347635721149 | | 2018 | 91.469328910436 | | 2017 | 91.377257473889 | | 2016 | 91.297423715917 | | 2015 | 91.070296772392 | | 2014 | 90.873116043088 | | 2013 | 89.866192062113 | | 2012 | 89.728295927517 | | 2011 | 89.883513236215 | | 2010 | 90.074339291952 | | 2009 | 88.810713727721 | | 2008 | 88.831431713377 | | 2007 | 88.702298783727 | | 2006 | 87.788156573454 | | 2005 | 87.771632223276 | | 2004 | 87.515259637587 | | 2003 | 87.340529003735 | | 2002 | 87.13025314555 | | 2001 | 88.081415918499 | | 2000 | 89.483041821789 | | 1999 | 89.158810191302 | | 1998 | 89.648023545892 | | 1997 | 89.682638570313 | | 1996 | 89.203774184958 | | 1995 | 89.194861446534 | | 1994 | 89.146467060557 | | 1993 | 88.628964909426 | | 1992 | 88.577341072951 | | 1991 | 88.51763600958 |
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