Year	Percent
1960	-65.15384
1961	-64.20165
1962	-32.46212
1963	-21.37462
1964	-18.29641
1965	-17.07819
1966	-21.21771
1967	-25.34249
1968	-26.84891
1969	-24.81859
1970	-23.02632
1971	-20.06764
1972	-23.47827
1973	-11.75496
1974	-6.24555
1975	-27.85888
1976	-26.17859
1977	-19.68096
1978	-17.34765
1979	-1.21569
1980	-0.11099
1981	-18.07273
1982	-13.23944
1983	6.18118
1984	16.00417
1985	0.78286
1986	-13.83483
1987	3.11342
1988	0.19727
1989	13.69539
1990	32.73536
1991	13.58463
1992	24.24349
1993	11.49655
1994	-15.70221
1995	1.09664
1996	8.50876
1997	15.4351
1998	3.6536
1999	13.18595
2000	36.68441
2001	24.10757
2002	27.57678
2003	4.76295
2004	29.69139
2005	29.65278
2006	18.53971
2007	25.00637
2008	28.149
2009	20.21255
2010	30.42174
2011	29.44732
2012	23.44588
2013	10.46048
2014	2.73412
2015	-27.09473
2016	-22.35042
2017	20.94612