Year % 1997 5.067001675041875 1999 5.978538579458355 2000 6.8406840684068415 2001 7.510040160642572 2003 7.91164658634538 2004 9.474590869939702 2005 9.836065573770496 2006 10.861561119293079 2007 13.721940622737149 2008 13.932242101256188 2009 15.095702419646083 2010 15.203426124196996 2011 16.256684491978604 2012 18.10099573257468 2013 18.27573922337015 2014 19.239052404881555 2015 19.1535150645624 2016 20.014372978799862 2017 20.833333333333332 2018 21.33190883190883 2019 23.548272176701108 2020 24.750000000000014 2021 26.423936553713048 2022 26.319648093841646 2023 26.1852662290299