Year	Percent
1960	1.15792
1961	1.12222
1962	1.04531
1963	1.17301
1964	1.00383
1965	1.39559
1966	1.37345
1967	1.45715
1968	1.26669
1969	1.026
1970	1.69643
1971	1.1185
1972	1.14199
1973	0.91075
1974	0.89831
1975	1.23149
1976	1.27139
1977	1.37214
1978	1.18112
1979	1.30668
1980	1.31685
1981	1.88945
1982	2.02572
1983	2.03593
1984	2.19085
1985	2.00737
1986	1.6675
1987	1.75071
1988	1.86908
1989	1.80285
1990	1.72801
1991	1.26844
1992	1.47262
1993	1.26706
1994	1.17853
1995	1.08043
1996	0.89572
1997	0.74282
1998	0.72084
1999	0.6756
2000	0.81834
2001	1.05206
2002	0.76224
2003	0.81566
2004	0.47942
2005	0.38391
2006	0.43183
2007	0.39846
2008	0.42542
2009	0.39066
2010	0.41076
2011	0.414
2012	0.44537
2013	0.46377
2014	0.41832
2015	0.39573
2016	0.42314
2017	0.37322