Year	Percent
1960	0.88961
1961	2.60619
1962	0.93199
1963	1.01743
1964	1.04194
1965	1.07469
1966	0.91306
1967	0.93261
1968	0.33303
1969	2.06732
1970	1.13052
1971	1.28738
1972	1.40078
1973	0.82781
1974	1.90896
1975	1.6011
1976	0.73962
1977	0.96368
1978	0.90488
1979	0.84241
1980	0.78401
1981	0.73882
1982	0.67854
1983	0.68151
1984	0.63441
1985	0.61137
1986	0.6093
1987	0.49183
1988	0.42664
1989	0.40939
1990	0.34137
1991	0.31036
1992	0.24824
1993	0.24682
1994	0.34069
1995	0.38179
1996	0.25319
1997	0.23827
1998	0.27173
1999	0.18259
2000	0.16728
2001	0.24095
2002	0.23253
2003	0.21398
2004	0.03366
2005	0.00939
2006	0.06337
2007	0.11491
2008	0.04843
2009	-0.01249
2010	0.01796
2011	-0.18523
2012	-0.15971
2013	-0.14427
2014	-0.13269
2015	-0.10612
2016	-0.11528
2017	-0.16448