Year	Percent
1965	1.18957
1966	1.32246
1967	1.36006
1968	2.06813
1969	2.42277
1970	2.4387
1971	2.28806
1972	2.18284
1973	2.62585
1974	2.977
1975	3.39945
1976	4.62671
1977	6.53813
1978	7.99131
1979	8.52052
1980	6.62909
1981	4.86432
1982	5.12255
1983	5.56085
1984	5.67765
1985	5.48667
1986	5.50382
1987	5.82389
1988	5.20871
1989	4.93103
1990	4.73941
1991	4.35168
1992	4.38939
1993	3.80572
1994	3.5976
1995	3.69693
1996	3.40987
1997	3.65082
1998	4.77976
1999	3.84077
2000	5.17638
2001	4.23024
2002	10.6747
2003	3.40108
2004	4.41126
2005	2.28315
2006	2.9703
2010	0.97784
2011	1.64382
2012	2.26393
2013	2.34308
2014	2.32473
2015	2.34363
2016	2.19817
2017	1.97058