| Year | Value | | 2022 | 76.797090243553 | | 2021 | 76.503510604394 | | 2020 | 76.232940730017 | | 2019 | 75.771879238309 | | 2018 | 74.778816417569 | | 2017 | 74.049856863864 | | 2016 | 73.390982596205 | | 2015 | 71.02482867726 | | 2014 | 67.917732502745 | | 2013 | 67.182183499006 | | 2012 | 66.640995778505 | | 2011 | 66.805055632341 | | 2010 | 64.830923657184 | | 2009 | 67.215500041533 | | 2008 | 67.422251625074 | | 2007 | 66.257028671869 | | 2006 | 66.138433957967 | | 2005 | 64.607274707137 | | 2004 | 65.387214185272 | | 2003 | 60.459937771695 | | 2002 | 60.237003971004 | | 2001 | 53.93260601204 | | 2000 | 53.912858903171 | | 1999 | 55.840745751777 | | 1998 | 57.951159636012 | | 1997 | 59.561491760189 | | 1996 | 62.919474781919 | | 1995 | 61.624878681577 | | 1994 | 64.868971151656 | | 1993 | 65.473204063493 | | 1992 | 66.028616376496 | | 1991 | 66.819469727503 |
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