Year Percent 2000 54.7618 2001 54.74352 2002 54.72525 2003 54.90841 2004 55.09142 2005 55.27431 2006 55.45706 2007 55.63967 2008 55.82215 2009 56.0045 2010 56.18671 2011 56.36879 2012 56.55073 2013 56.73254 2014 56.91421 2015 57.09575 2016 57.27716 2017 57.45843 2018 57.63956 2019 57.82056 2020 58.00143 2021 58.18216 2022 58.18216