Year	Percent
1960	4.27239
1961	4.78131
1962	4.93106
1963	4.83936
1964	4.78288
1965	4.73435
1966	4.15472
1967	2.65049
1968	2.62066
1969	2.62897
1970	2.66237
1971	2.80717
1972	2.83439
1973	2.80675
1974	2.77922
1975	2.70407
1976	2.65614
1977	2.60252
1978	1.13445
1979	0.68493
1980	0.68027
1981	0.65372
1982	0.6131
1983	0.60936
1984	0.67035
1985	0.72296
1986	0.82393
1987	0.90135
1988	0.78903
1989	0.46491
1990	0.79984
1991	1.52664
1992	1.52367
1993	1.26429
1994	1.38483
1995	1.74275
1996	2.21923
1997	1.93893
1998	1.55343
1999	1.33973
2000	1.99983
2001	2.84749
2002	2.76315
2003	2.23224
2004	1.71884
2005	1.64295
2006	1.11826
2007	0.61589
2008	0.56125
2009	0.54294
2010	0.55008
2011	0.51202
2012	0.4546
2013	0.49719
2014	0.52927
2015	0.58045
2016	0.64535
2017	0.6751