Year	Percent
1984	16.73
1990	23.43
1991	24.35
1992	23.88
1993	22.87
1994	24.11
1995	24.63
1998	23.04
1999	24.53
2000	29.07
2001	34.28
2002	37.96
2003	38.18
2004	33.02
2005	29.19
2006	28.11
2007	25.04
2008	22.44
2009	21.07
2010	20.71
2011	18.13
2012	18.51
2013	19.26
2014	19.43
2015	22.54
2016	23.78
2017	24.78
2018	25.92
2019	27.81
2020	33.45