Year	Percent
1976	4.4237
1977	5.1264
1978	5.4443
1979	4.8629
1980	5.1011
1981	5.2223
1982	8.7465
1983	9.9468
1984	9.478
1985	8.7022
1986	7.8828
1987	7.1795
1988	6.2813
1989	6.3033
1990	7.1788
1991	9.4211
1992	10.6666
1993	10.5457
1994	9.621
1995	8.6644
1996	8.78
1997	7.945
1998	7.176
1999	6.5075
2000	5.7258
2001	6.3114
2002	6.8462
2003	6.5496
2004	6.1265
2005	5.8245
2006	5.3561
2007	5.3345
2008	5.3788
2009	8.0673
2010	7.3967
2011	6.4751
2012	6.2919
2013	6.1225
2014	6.0283
2015	6.1843
2016	6.4822
2017	5.6357