| Year | Value | | 2022 | 46.746766809373 | | 2021 | 46.889742413011 | | 2020 | 46.677008212598 | | 2019 | 47.6832084081 | | 2018 | 47.49855499517 | | 2017 | 47.066409082331 | | 2016 | 47.17038533663 | | 2015 | 46.258267026939 | | 2014 | 45.706005185899 | | 2013 | 45.089651643013 | | 2012 | 44.557626448002 | | 2011 | 43.651020075698 | | 2010 | 42.911411161498 | | 2009 | 42.456799951962 | | 2008 | 42.187029819633 | | 2007 | 41.70283264459 | | 2006 | 41.166186996149 | | 2005 | 40.670691068209 | | 2004 | 39.944966333972 | | 2003 | 39.267188680044 | | 2002 | 38.943348007321 | | 2001 | 38.522650512904 | | 2000 | 38.040014222708 | | 1999 | 37.729264271309 | | 1998 | 37.447657216033 | | 1997 | 37.401872143948 | | 1996 | 37.149649162665 | | 1995 | 36.874788424433 | | 1994 | 36.701532374616 | | 1993 | 36.569717322775 | | 1992 | 36.446316701724 | | 1991 | 36.345235330454 |
|