Year Percent 2000 98.3686 2001 98.41415 2002 98.4597 2003 98.50525 2004 98.55079 2005 98.50267 2006 98.45445 2007 98.40615 2008 98.35776 2009 98.30929 2010 98.26073 2011 98.21208 2012 98.16335 2013 98.11453 2014 98.06562 2015 98.01663 2016 97.96755 2017 97.91838 2018 97.86913 2019 97.81979 2020 97.77036 2021 97.72085 2022 97.76566