Year Percent 2000 31.16604 2001 32.51812 2002 33.86738 2003 35.21381 2004 36.55742 2005 37.8982 2006 39.23616 2007 40.57129 2008 41.90359 2009 43.23307 2010 44.55972 2011 45.88354 2012 47.20454 2013 48.52271 2014 49.83806 2015 51.15058 2016 52.46028 2017 53.76714 2018 55.07119 2019 56.3724 2020 57.67079 2021 58.96636 2022 60.2591