Year % of expense 2012 5.0449293819222705 2014 4.963860828035562 2015 5.995543883886894 2016 7.5884500177158625 2017 7.885434605275083 2018 10.582178375769388 2019 8.085825657449721 2020 9.553124927534068 2021 10.493148733286274