Year Percent 2000 24.13493 2001 24.67644 2002 25.21787 2003 25.75921 2004 26.30046 2005 26.84163 2006 27.3827 2007 27.92369 2008 28.46459 2009 29.0054 2010 29.54613 2011 30.08676 2012 30.62731 2013 31.16777 2014 31.70815 2015 32.24843 2016 32.78863 2017 33.32874 2018 33.86876 2019 34.4087 2020 34.94855 2021 35.4883 2022 36.02798