| Year | Value | | 2022 | 60.817453767108 | | 2021 | 60.565851091305 | | 2020 | 60.335293910471 | | 2019 | 61.294126003267 | | 2018 | 60.309447550083 | | 2017 | 60.149508209178 | | 2016 | 59.872393371786 | | 2015 | 59.769461488698 | | 2014 | 58.799860564713 | | 2013 | 57.65552418253 | | 2012 | 56.550254308836 | | 2011 | 55.514763727907 | | 2010 | 54.362824675325 | | 2009 | 53.22578826289 | | 2008 | 52.462095027421 | | 2007 | 51.517622863627 | | 2006 | 50.835815451948 | | 2005 | 50.356863603666 | | 2004 | 49.918236483267 | | 2003 | 49.387196256713 | | 2002 | 48.776025667281 | | 2001 | 48.413055395471 | | 2000 | 48.107455172763 | | 1999 | 47.633467922835 | | 1998 | 47.394188372111 | | 1997 | 47.098091447804 | | 1996 | 46.895508149805 | | 1995 | 46.621420491754 | | 1994 | 46.491775607269 | | 1993 | 46.381662957423 | | 1992 | 46.442829165411 | | 1991 | 46.4012458528 |
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