Year Percent 2000 18.6823 2001 20.23204 2002 21.77133 2003 23.29816 2004 24.81318 2005 26.31637 2006 27.80829 2007 29.29771 2008 30.87521 2009 32.43838 2010 33.98875 2011 35.52505 2012 37.0482 2013 38.54823 2014 40.03466 2015 41.50686 2016 42.96516 2017 44.4085 2018 45.83816 2019 47.25398 2020 48.65535 2021 50.04256 2022 51.51296