Year	Percent
1965	-2.42446
1966	-5.11662
1967	-3.01987
1968	-1.75487
1969	-2.6072
1970	0.28599
1971	-1.98294
1972	0.96857
1973	-3.02291
1974	-8.41357
1975	-5.16952
1976	-1.27304
1977	0.69213
1978	-9.26355
1979	-0.16976
1980	0.91663
1981	-6.90911
1982	-5.69293
1983	-5.42077
1984	-6.7824
1985	-7.56301
1986	-4.3778
1987	-7.11001
1988	-6.47434
1989	-10.45272
1990	-12.62165
1991	-13.30188
1992	-16.40941
1993	-14.78268
1994	-15.3032
1995	-16.25175
1996	-12.99988
1997	-11.51342
1998	-12.09912
1999	-12.19769
2000	-15.05555
2001	-15.87215
2002	-14.89291
2003	-16.39014
2004	-17.96984
2005	-19.18271
2006	-21.57621
2007	-26.48699
2008	-27.18481
2009	-18.16879
2010	-19.64395
2011	-21.31308
2012	-20.54881
2013	-21.28004
2014	-19.28303
2015	-18.11955
2016	-16.22994
2017	-17.27221