Year	Percent
1976	4.21
1977	5.19
1978	5.61
1979	4.74
1980	4.68
1981	4.57
1982	7.08
1983	8.42
1984	8.14
1985	8.39
1986	7.45
1987	7.12
1988	6.33
1989	6.36
1990	6.09
1991	8.26
1992	9.29
1993	9.96
1994	9.19
1995	8.33
1996	7.81
1997	7.6
1998	6.86
1999	5.95
2000	5.48
2001	5.82
2002	6.26
2003	6.27
2004	5.92
2005	5.37
2006	5.23
2007	5.06
2008	5.37
2009	6.96
2010	6.59
2011	6.63
2012	6.2
2013	6.33
2014	6.15
2015	6.08
2016	6.36
2017	5.77
2018	5.38
2019	5.31
2020	7.98