Year Percent 2000 99.40387 2001 99.39908 2002 99.39428 2003 99.38949 2004 99.38469 2005 99.3799 2006 99.3751 2007 99.3703 2008 99.36549 2009 99.36069 2010 99.35588 2011 99.35108 2012 99.34627 2013 99.34146 2014 99.33664 2015 99.33183 2016 99.32701 2017 99.32219 2018 99.31012 2019 99.29804 2020 99.28596 2021 99.28596 2022 99.28596