Year % of expense 2014 2.9420476618627167 2015 3.4935369140736583 2016 3.980226221223421 2017 3.336584973457008 2018 4.015109707602598 2019 3.7167029714455326 2020 3.750544628604583 2021 2.981700951780248 2022 3.1939055336337208