Year % of expense 2006 33.51130588646791 2007 35.33673445616978 2008 46.13466876551366 2009 33.884697261523755 2010 37.45387181547272 2011 36.43941120400868 2012 30.777424234160094 2013 27.17148545385526 2014 24.201137469263738 2015 8.946902450349842 2016 8.3352653607837 2017 8.335573607659189 2018 9.702797265412261 2019 8.955773635772115 2020 7.476410695631168 2021 12.40387822895684 2022 15.329965941228371