Year % 2001 9.242695433014099 2002 7.832117560598947 2003 9.3800399559659 2004 10.591989197089504 2005 10.534176366621704 2006 9.933846352409786 2007 7.983063789344191 2008 8.020313594323339 2009 7.736878805917359 2010 7.381218444581935 2011 7.159154219549286 2012 7.1794817449404285 2013 7.104969997986838 2014 7.042887035250793 2015 6.858324756712609 2016 6.414033027825254 2017 6.137839991743899 2018 5.509573834387578 2019 5.167204407588243 2020 5.394103277269152 2021 4.626401831970228 2022 4.808024763315461 2023 3.921506364256902