| Year | Value | | 2022 | 52.251569362445 | | 2021 | 51.926961080654 | | 2020 | 51.565667794928 | | 2019 | 51.890708681773 | | 2018 | 51.360012839376 | | 2017 | 50.788230406494 | | 2016 | 50.383981041064 | | 2015 | 49.814528760874 | | 2014 | 48.936511163284 | | 2013 | 48.207015970891 | | 2012 | 47.508287210728 | | 2011 | 46.610684839563 | | 2010 | 45.623430063929 | | 2009 | 44.724654302321 | | 2008 | 43.881464724798 | | 2007 | 42.923379580986 | | 2006 | 42.15410655357 | | 2005 | 41.256213556976 | | 2004 | 40.268527801124 | | 2003 | 39.04558680209 | | 2002 | 38.398482171137 | | 2001 | 37.775160406991 | | 2000 | 36.73490271282 | | 1999 | 36.152685906297 | | 1998 | 35.641600454255 | | 1997 | 35.287790001584 | | 1996 | 34.465976856189 | | 1995 | 33.699445636113 | | 1994 | 32.97142480116 | | 1993 | 32.294928761374 | | 1992 | 31.594801636916 | | 1991 | 31.136105051553 |
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