Year	Percent
2004	29.32
2005	26.03
2006	23.66
2008	18.84
2009	21.17
2010	19.36
2011	18.73
2012	18.28
2013	19.43
2014	18.84
2017	22.64
2018	23.73
2019	25.86
2020	30.17