Year Percent 2000 8.05081 2001 10.41389 2002 12.76716 2003 15.06599 2004 17.34002 2005 19.58857 2006 21.81185 2007 24.00108 2008 26.16652 2009 28.30788 2010 30.4253 2011 32.51866 2012 34.58343 2013 36.62644 2014 38.64773 2015 40.64731 2016 42.62515 2017 44.5813 2018 46.5156 2019 48.42792 2020 50.31808 2021 50.29887 2022 50.27919