Year Percent 2006 95.18597 2007 95.43022 2008 95.67469 2009 95.9193 2010 96.16409 2011 96.4091 2012 96.65431 2013 96.89975 2014 97.14541 2015 97.3913 2016 97.63739 2017 97.88369 2018 98.5063 2019 98.6814 2020 98.85691 2021 98.86039 2022 98.86387