Year	Percent
1983	24.75
1984	25.22
1986	17.3
1988	14.33
1989	13.22
1990	13.06
1991	12.7
1992	10.9
1993	10.95
1994	13.18
1995	11.5
1996	18.21
1997	17.84
1998	18.1
1999	25.66
2000	25.05
2001	24.78
2002	25.23
2003	24.97
2004	24.56
2005	23.42
2006	22.08
2007	21.54
2008	23.69
2009	26.68
2010	19
2011	17.88
2012	16.7
2013	16.62
2014	16.97
2015	16.05
2016	15.98
2017	17.19
2018	18.15
2019	19.58
2020	24.91