| Year | Value | | 2022 | 82.59801121 | | 2021 | 82.74901607 | | 2020 | 80.53018608 | | 2019 | 81.20259644 | | 2018 | 73.47972844 | | 2017 | 71.58166462 | | 2016 | 65.88044919 | | 2015 | 59.76295014 | | 2014 | 53 | | 2013 | 45.96 | | 2012 | 47.5 | | 2011 | 39.212196 | | 2010 | 36.5 | | 2009 | 34.33 | | 2008 | 32.29 | | 2007 | 28.4 | | 2006 | 25.1 | | 2005 | 22.07 | | 2004 | 20.79230671 | | 2003 | 20.33361481 | | 2002 | 19.89485113 | | 2001 | 9.559482135 | | 2000 | 5.800253023 | | 1999 | 3.904323257 | | 1998 | 2.666378698 | | 1997 | 1.640221288 | | 1996 | 0.84105704 | | 1995 | 0.416829206 | | 1994 | 0.279912479 | | 1993 | 0.081509754 | | 1992 | 0.001113325 |
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