Year	Percent
1991	40.22
2002	36.31
2003	35.82
2004	32.76
2005	32.26
2006	28.88
2007	25.18
2008	23.68
2009	25.24
2010	32.37
2011	36.65
2012	42.08
2013	50.01
2014	45.51
2015	42.33
2016	31.27
2017	27.35
2018	23.71
2019	16.63
2020	21.11