Year	Percent
1960	1.18305
1961	1.18327
1962	1.08286
1963	0.89779
1964	0.85173
1965	0.85261
1966	0.87292
1967	0.84514
1968	0.79453
1969	0.8074
1970	0.91664
1971	1.36263
1972	1.18581
1973	0.87481
1974	0.79509
1975	0.80359
1976	0.65924
1977	0.68437
1978	0.803
1979	0.83446
1980	0.76578
1981	0.6268
1982	0.54474
1983	0.88914
1984	0.92243
1985	3.16077
1986	2.69666
1987	3.39315
1988	2.37118
1989	1.7986
1990	2.32849
1991	3.08209
1992	3.36764
1993	3.43179
1994	3.72934
1995	5.86113
1996	5.51978
1997	4.6306
1998	4.64346
1999	4.03016
2000	5.03387
2001	4.28699
2002	3.34259
2003	2.86891
2004	2.99736
2005	2.63953
2006	2.79877
2007	3.26061
2008	3.71217
2009	3.61866
2010	2.70075
2011	2.68316
2012	2.1552
2013	2.15405
2014	2.41265
2015	2.5528
2016	2.14256
2017	2.17197