Year Percent 2006 96.00295 2007 96.23909 2008 96.4754 2009 96.7119 2010 96.94858 2011 97.18543 2012 97.42247 2013 97.65969 2014 97.8971 2015 98.13468 2016 98.37244 2017 98.61039 2018 98.80889 2019 99.00031 2020 99.19174 2021 99.19174 2022 99.19174