Year	Percent
1983	6.6602
1984	7.0808
1985	7.4806
1986	7.1891
1987	7.9845
1988	8.0364
1989	7.4555
1990	7.2047
1991	7.7032
1992	8.028
1993	7.354
1994	6.2479
1995	6.0047
1996	7.9763
1997	7.6863
1998	8.6979
1999	7.7361
2000	7.4233
2001	6.3027
2002	4.6075
2003	4.0738
2004	6.7972
2005	4.382
2006	4.7166
2007	4.087
2008	3.7313
2009	5.1137
2010	5.483
2011	5.648
2012	5.9207
2013	6.4972
2014	6.865
2015	6.7631
2016	6.2954
2017	5.7467