Year | Value | 2021 | 21.270709374165 | 2020 | 19.980014505594 | 2019 | 19.965926702991 | 2018 | 16.783906554699 | 2017 | 16.650647051704 | 2016 | 16.93159775162 | 2015 | 16.694862685389 | 2014 | 15.836337850221 | 2013 | 15.601214639199 | 2012 | 15.52996015015 | 2011 | 15.482376950559 | 2010 | 15.964973466168 | 2009 | 17.040128802397 | 2008 | 20.482033916219 | 2007 | 20.36935435219 | 2006 | 20.484203180347 | 2005 | 19.754629223377 | 2004 | 19.36200926592 | 2003 | 19.063854429755 | 2002 | 19.20183971047 | 2001 | 19.404629211765 | 2000 | 20.300373277697 | 1999 | 22.213817150752 | 1998 | 22.186709547089 | 1997 | 21.646091447724 | 1996 | 18.90896741467 | 1995 | 19.824546890877 |
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