Year Percent 2000 38.79994 2001 39.4958 2002 40.19166 2003 40.88752 2004 41.58339 2005 42.27925 2006 42.97511 2007 43.67097 2008 44.36684 2009 45.0627 2010 45.75856 2011 46.80532 2012 47.86259 2013 48.93038 2014 50.00867 2015 51.09748 2016 52.19681 2017 53.30664 2018 54.42699 2019 55.55785 2020 56.69922 2021 57.85111 2022 59.01351