Year	Percent
1976	5.29
1977	6.03
1978	6.44
1979	5.78
1980	5.76
1981	5.96
1982	8.9
1983	9.95
1984	9.77
1985	9.11
1986	8.29
1987	7.74
1988	6.91
1989	6.82
1990	7.35
1991	9.25
1992	10.04
1993	10.27
1994	9.35
1995	8.5
1996	8.64
1997	7.83
1998	7.06
1999	6.43
2000	5.75
2001	6.18
2002	6.57
2003	6.44
2004	6.01
2005	5.76
2006	5.3
2007	5.06
2008	5.09
2009	7.13
2010	6.92
2011	6.26
2012	6.04
2013	5.87
2014	5.75
2015	5.83
2016	5.96
2017	5.41
2018	4.92
2019	4.71
2020	7.75