Year	Percent
1961	3.04412
1962	6.79042
1963	8.56707
1964	4.511
1965	3.97651
1966	5.33479
1967	1.96339
1968	6.40814
1969	5.88574
1970	15.1555
1971	14.39922
1972	6.51174
1973	16.87134
1974	32.59974
1975	9.31583
1976	8.30454
1977	8.27288
1978	9.33174
1979	14.83954
1980	14.24995
1981	11.70314
1982	8.70122
1983	14.22188
1984	53.33596
1985	17.63286
1986	2.95288
1987	7.49819
1988	9.64702
1989	9.03306
1990	12.97128
1991	16.52688
1992	7.93266
1993	6.83216
1994	9.99131
1995	7.55087
1996	7.66104
1997	6.22439
1998	22.38172
1999	6.58506
2000	5.7098
2001	5.54948
2002	4.16223
2003	3.20133
2004	5.51689
2005	5.82801
2006	4.94902
2007	3.09033
2008	7.54906
2009	2.77325
2010	4.22239
2011	4.02172
2012	1.96838
2013	2.04547
2014	3.15744
2015	-0.58657
2016	1.6991
2017	2.32071