Year	Percent
1960	0.68943
1961	-0.91765
1962	-0.06135
1963	-1.67279
1964	-4.09344
1965	-3.70388
1966	-2.36754
1967	-3.28958
1968	-3.27552
1969	-3.51934
1970	-4.19437
1971	-4.4361
1972	-8.05783
1973	-5.31584
1974	-6.64747
1975	-5.20547
1976	-12.89011
1977	-5.34069
1978	-9.92319
1979	-9.68862
1980	-12.38866
1981	-8.98543
1982	-10.45632
1983	-9.10918
1984	-10.01922
1985	-7.45323
1986	-6.65288
1987	-6.7077
1988	-6.82146
1989	-7.24489
1990	-7.14987
1991	-5.5646
1992	-4.76065
1993	-5.08704
1994	-4.86278
1995	-6.48023
1996	-6.66307
1997	-5.28477
1998	-4.3654
1999	-4.87066
2000	-4.63331
2001	-5.3249
2002	-4.14744
2003	-4.79559
2004	-4.56522
2005	-5.61125
2006	-5.405
2007	-5.95171
2008	-7.3032
2009	-6.21253
2010	-5.75462
2011	-7.5767
2012	-7.78775
2013	-7.22065
2014	-6.53476
2015	-7.41265
2016	-4.65487
2017	-5.23178