Year | Value | 2022 | 36.936302232238 | 2021 | 36.619504024876 | 2020 | 34.855068707703 | 2019 | 34.733419975718 | 2018 | 35.568974589114 | 2017 | 35.555595311118 | 2016 | 34.988916836382 | 2015 | 35.938891614115 | 2014 | 37.518406566259 | 2013 | 37.666727123772 | 2012 | 38.67461311523 | 2011 | 39.462467091882 | 2010 | 40.053002761794 | 2009 | 38.504683234028 | 2008 | 40.999708250556 | 2007 | 40.417805530124 | 2006 | 39.207016412871 | 2005 | 37.468975575525 | 2004 | 37.173903217216 | 2003 | 34.541108992734 | 2002 | 32.263007377785 | 2001 | 31.561195427459 | 2000 | 31.184149040856 | 1999 | 30.476067238834 | 1998 | 30.818373053874 | 1997 | 31.998164366546 | 1996 | 32.023211660553 | 1995 | 32.736857614892 | 1994 | 35.612104174178 | 1993 | 36.379858546415 | 1992 | 35.467954229037 | 1991 | 31.108310697259 | 1990 | 32.576999284881 | 1989 | 34.857317660038 | 1988 | 34.924488434966 | 1987 | 33.771081877986 | 1986 | 31.398073374015 | 1985 | 31.413793135697 | 1984 | 30.822770527348 | 1983 | 28.951751234495 | 1982 | 29.527933765853 |
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