Year	Percent
1983	23.61
1984	23.22
1986	16.53
1988	12.54
1989	12.25
1990	13.35
1991	11.54
1992	9.73
1993	10.33
1994	12.02
1995	10.83
1996	14.984
1997	14.3
1998	15.147
1999	22.03
2000	21.172
2001	21.864
2002	21.952
2003	20.742
2004	20.213
2005	18.767
2006	18.493
2007	18.137
2008	19.911
2009	23.537
2010	17.1413
2011	15.6067
2012	14.7812
2013	14.5516
2014	14.888
2015	14.3235
2016	14.7051
2017	16.1038