Year % of expense 2009 5.8067137464837915 2010 5.326732429915425 2011 4.4685326404810075 2012 5.067173911961976 2013 4.447871869174403 2014 4.963860828035562 2015 5.995543883886894 2016 7.709051677110263 2017 7.885434605275083 2018 9.424207176075342 2019 8.085825657449721 2020 9.11732636793582 2021 10.493148733286274