Year Percent 2011 41.16322 2012 41.2372 2013 41.27469 2014 41.27738 2015 41.24751 2016 41.18681 2017 41.09733 2018 40.98151 2019 40.84166 2020 40.95093 2021 41.06566 2022 41.18659