Year	Percent
2004	15.71
2005	14.89
2009	17.79
2010	17.36
2011	18.64
2012	17.29
2013	17.39
2014	23.14
2015	22.36
2016	22.95
2017	18.92
2018	17.95
2019	15.41
2020	19.26