Year % 2001 16.484847385444013 2002 17.40370572542913 2003 16.680747524585176 2004 20.51597424933391 2005 18.038346663147724 2006 17.617572656611785 2007 18.61560770822176 2008 16.960122272057124 2009 21.059597539513874 2010 20.846852367020077 2011 19.531680386825407 2012 18.73097573009395 2013 20.14074090331465 2014 19.18280516153737 2015 20.762102311467064 2016 22.568098512944598 2017 22.703584807565058 2018 22.023917852226564 2019 20.646344098670948 2020 24.64224559065119 2021 22.94856493980269 2022 22.83696317854561 2023 18.435734215107747