Year | Value | 2021 | 27.965217829235 | 2020 | 31.162488988198 | 2019 | 30.353996615538 | 2018 | 29.180088233738 | 2017 | 31.694632926215 | 2016 | 30.096305972243 | 2015 | 33.422386866616 | 2014 | 34.628688101059 | 2013 | 32.980719337197 | 2012 | 32.932751442592 | 2011 | 29.55059042182 | 2010 | 25.542315977769 | 2009 | 29.072305263312 | 2008 | 29.70119351839 | 2007 | 30.525290604962 | 2006 | 29.072166606465 | 2005 | 25.729009877012 | 2004 | 24.272821743486 | 2003 | 23.194769224006 | 2002 | 26.061996674152 | 2001 | 26.309462849395 | 2000 | 27.428509040792 | 1999 | 27.915128008677 | 1998 | 25.693487732074 | 1997 | 26.668706009627 | 1996 | 23.986629478752 | 1995 | 25.018694549563 | 1994 | 24.088614886901 | 1993 | 26.130345459808 | 1992 | 25.105704719309 | 1991 | 26.957330526297 | 1990 | 23.01056488446 |
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