Year Percent 2000 20.6835 2001 21.28552 2002 21.88798 2003 22.49057 2004 23.09361 2005 23.81846 2006 24.55142 2007 25.29236 2008 26.04116 2009 26.79708 2010 27.56061 2011 28.33161 2012 29.10965 2013 29.89462 2014 30.68639 2015 31.48752 2016 32.29726 2017 33.11574 2018 33.9428 2019 34.77797 2020 35.62107 2021 36.29104 2022 36.96208