Year	Percent
1983	6.088
1984	7.64
1985	8.4899
1986	8.6848
1987	8.6476
1988	8.1718
1989	7.3102
1990	7.1746
1991	7.1635
1992	8.0912
1993	9.6148
1994	11.0265
1995	9.9788
1996	10.5879
1997	11.0144
1998	10.3548
1999	10.3536
2000	8.5349
2001	7.0001
2002	7.772
2003	7.5865
2004	8.0752
2005	7.8074
2006	7.858
2007	7.2715
2008	6.7223
2009	8.6767
2010	8.6947
2011	8.5337
2012	9.4382
2013	10.041
2014	10.5352
2015	10.7993
2016	10.2454
2017	9.4538