Year	Percent
1960	1.11432
1961	1.44339
1962	1.96026
1963	1.7605
1964	1.83043
1965	1.83359
1966	1.40411
1967	1.00152
1968	0.91619
1969	1.13747
1970	1.13063
1971	1.67973
1972	2.02666
1973	1.89461
1974	2.07622
1975	1.84567
1976	1.22936
1977	0.88927
1978	0.87688
1979	0.91329
1980	1.01899
1981	0.79587
1982	0.15271
1983	0.09613
1984	0.17233
1985	0.26267
1986	0.51823
1987	0.7161
1988	0.79485
1989	1.04067
1990	1.3209
1991	1.56551
1992	1.81761
1993	1.74522
1994	2.12262
1995	1.90182
1996	1.27898
1997	1.19805
1998	1.38147
1999	2.01787
2000	2.26003
2001	1.93231
2002	1.58375
2003	1.7343
2004	1.92637
2005	2.01739
2006	2.06848
2007	2.00297
2008	2.23391
2009	2.28128
2010	2.2431
2011	2.62729
2012	2.78651
2013	2.6746
2014	2.70257
2015	2.68753
2016	2.46649
2017	3.24632