Year | Value | 2022 | 13.603677149744 | 2021 | 13.459471924262 | 2020 | 13.41286711994 | 2019 | 14.126365591981 | 2018 | 14.712574203317 | 2017 | 15.20372054602 | 2016 | 15.730366209465 | 2015 | 16.227850267922 | 2014 | 16.599606739282 | 2013 | 16.96278944616 | 2012 | 17.36697999261 | 2011 | 16.249181967293 | 2010 | 15.133420415058 | 2009 | 14.056597279228 | 2008 | 13.083030232233 | 2007 | 12.053655611885 | 2006 | 11.135085873394 | 2005 | 10.344087137128 | 2004 | 10.032258052097 | 2003 | 9.8134570045333 | 2002 | 9.7976694387169 | 2001 | 9.8879141560912 | 2000 | 10.031139998347 | 1999 | 10.283945089547 | 1998 | 10.385228529197 | 1997 | 10.512712452059 | 1996 | 10.655630197248 | 1995 | 10.878249618946 | 1994 | 11.116727540379 | 1993 | 11.391376704072 | 1992 | 11.667497031721 | 1991 | 11.829585689974 |
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