Year	Percent
1960	2.17227
1961	1.97862
1962	2.53501
1963	2.13766
1964	1.65426
1965	1.15484
1966	1.04515
1967	1.23905
1968	1.25926
1969	1.12542
1970	0.7224
1971	0.52479
1972	0.76248
1973	0.73823
1974	0.53852
1975	-0.04374
1976	-0.5716
1977	-0.33901
1978	0.00898
1979	0.20081
1980	0.39707
1981	0.54706
1982	0.58429
1983	0.42879
1984	0.35911
1985	0.44144
1986	0.52039
1987	0.62812
1988	0.73494
1989	0.80854
1990	1.02687
1991	1.24983
1992	1.10252
1993	0.91072
1994	0.79716
1995	0.66824
1996	0.44164
1997	0.24089
1998	0.29714
1999	0.47692
2000	0.56195
2001	0.63277
2002	0.75647
2003	0.74192
2004	0.68743
2005	0.6406
2006	0.62756
2007	0.89369
2008	1.27062
2009	1.24948
2010	1.04156
2011	1.11188
2012	1.06182
2013	1.14988
2014	1.2201
2015	1.13834
2016	1.09203
2017	1.10075