Year % of expense 2009 8.95284566153291 2010 11.106449096413552 2011 9.99223830271714 2012 9.159813141747094 2013 8.734007236514566 2014 17.20950854308578 2015 15.856091558099559 2016 17.947932885715883 2017 21.402982929070312 2018 17.62944496611418 2019 18.469683477540084 2020 17.986431839435944 2021 20.31515033571078 2022 26.347641302375703