Year	Percent
1983	9.49
1984	9.66
1985	9.47
1986	9.8
1987	9.79
1988	9.1
1989	7.5
1990	6.47
1991	6.29
1992	6.09
1993	7.07
1994	8.41
1995	8.26
1996	8.56
1997	7.88
1998	8.37
1999	7.38
2000	5.83
2001	5.39
2002	6.2
2003	6.95
2004	6.59
2005	7.39
2006	7.24
2007	6.59
2008	6.1
2009	6.78
2010	7.31
2011	6.37
2012	6.74
2013	7.37
2014	7.62
2015	7.68
2016	7.11
2017	6.25
2018	5.37
2019	4.77
2020	4.99