Year	Percent
1960	3.14918
1961	3.00688
1962	2.84589
1963	2.65139
1964	2.42312
1965	2.17468
1966	1.92244
1967	1.69357
1968	1.50882
1969	1.38928
1970	1.3121
1971	1.23361
1972	1.15128
1973	1.09763
1974	1.0807
1975	1.0776
1976	1.10139
1977	1.09765
1978	1.005
1979	0.79269
1980	0.50103
1981	0.20219
1982	-0.06219
1983	-0.29458
1984	-0.47987
1985	-0.61903
1986	-0.77869
1987	-0.91369
1988	-0.89841
1989	-0.6771
1990	-0.31646
1991	0.13176
1992	0.51527
1993	0.71257
1994	0.64267
1995	0.38812
1996	0.07484
1997	-0.17749
1998	-0.33692
1999	-0.35342
2000	-0.2621
2001	-0.13789
2002	-0.05039
2003	-0.00359
2004	-0.02727
2005	-0.09397
2006	-0.17927
2007	-0.23132
2008	-0.20814
2009	-0.08324
2010	0.11566
2011	0.34019
2012	0.53136
2013	0.66042
2014	0.69827
2015	0.66858
2016	0.62122
2017	0.58743