Year % of expense 2011 44.54289103398819 2012 40.6966139243754 2013 39.31528000153605 2014 42.03521988914283 2015 38.56991963370914 2016 35.08467637586896 2017 33.462185852677656 2018 41.17668708943103 2019 38.0937464102495 2020 33.72111162802211 2021 32.30995546815083 2022 32.77196310898004