Year % 1997 8.939566704675032 1998 9.340300457217507 1999 9.11934552454283 2001 11.915747241725168 2002 13.515298261060972 2003 13.521344407958278 2004 14.05745368009519 2005 16.89596537331891 2006 17.112055876100825 2007 17.634474327628364 2008 17.59216052263183 2009 17.71402550091075 2010 18.31363278171789 2011 20.35370772572138 2012 21.49832163564236 2013 22.10526315789474 2014 22.150197628458507 2015 23.8495575221239 2016 24.02894697976665 2017 24.309313585872975 2018 24.050267225191394 2019 24.122612172367845 2020 25.23581258698006 2021 26.45264847512039 2022 26.57920310981536 2023 27.29516288252715