Year Percent 2000 13.01621 2001 13.35448 2002 13.6935 2003 14.03329 2004 14.37384 2005 14.71515 2006 15.05722 2007 15.40004 2008 15.74363 2009 16.08798 2010 16.43308 2011 16.77895 2012 17.12557 2013 17.47296 2014 17.8211 2015 18.17001 2016 18.51967 2017 18.87009 2018 19.22128 2019 19.55068 2020 19.55068 2021 19.55068 2022 19.55068