Year | Value | 2022 | 33.769473111313 | 2021 | 33.384620266727 | 2020 | 31.592981937947 | 2019 | 31.881195334313 | 2018 | 32.61074187417 | 2017 | 32.464535733111 | 2016 | 31.844214513738 | 2015 | 32.469207446537 | 2014 | 33.759113935658 | 2013 | 33.871691427321 | 2012 | 34.938680980183 | 2011 | 35.693662148692 | 2010 | 36.381546130281 | 2009 | 35.074217256516 | 2008 | 37.4027901468 | 2007 | 36.846859781024 | 2006 | 35.965326251708 | 2005 | 34.175264817906 | 2004 | 33.699752369499 | 2003 | 31.536406718523 | 2002 | 29.880605838792 | 2001 | 28.994945287777 | 2000 | 28.731613699871 | 1999 | 27.974323753303 | 1998 | 28.545964462678 | 1997 | 29.347095473215 | 1996 | 29.331461018172 | 1995 | 29.739835171574 | 1994 | 31.303792657264 | 1993 | 31.26125909691 | 1992 | 30.191247767258 | 1991 | 29.029161525167 | 1990 | 28.223990654305 | 1989 | 29.461771143786 | 1988 | 29.957326920791 | 1987 | 28.911987129676 | 1986 | 27.422668385829 | 1985 | 28.348698568501 | 1984 | 27.366072351878 | 1983 | 26.558723943374 | 1982 | 26.612479511117 |
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