Year	Percent
1980	7.50969
1981	7.52548
1982	7.82733
1983	7.86314
1984	8.02519
1985	7.90092
1986	8.55709
1987	8.20425
1988	8.58731
1989	8.05825
1990	8.09388
1991	7.85052
1992	8.01419
1993	7.38825
1994	7.92278
1995	8.00404
1996	8.44204
1997	8.41819
1998	9.3921
1999	9.03779
2000	10.20462
2001	9.21083
2002	9.1932
2003	9.19074
2004	9.22392
2005	9.42933
2006	9.52176
2007	9.35967
2008	9.91292
2009	9.68154
2010	9.71923
2011	9.65174
2012	9.52037
2013	9.60282
2014	9.40177
2015	9.84947
2016	9.76821