Year	Percent
1971	-3.88084
1972	10.38395
1973	19.1505
1974	43.22929
1975	3.83784
1976	-27.8253
1977	-6.01129
1978	-0.43364
1979	-12.86046
1980	-17.6798
1981	-4.58254
1982	5.45742
1983	-2.1619
1984	3.17338
1985	-8.72345
1986	-3.11968
1987	-11.52052
1988	6.27187
1989	-5.76435
1990	-2.99422
1991	-1.74763
1992	-0.56509
1993	-0.39598
1994	0.46106
1995	-1.36241
1996	0.178
1997	0.04754
1998	4.77249
1999	-3.21893
2000	4.43733
2001	-3.13688
2002	2.02288
2003	0.22542
2004	-3.41877
2005	2.92478
2006	-3.60138
2007	0.02572
2008	-3.97022
2009	-1.83249
2010	-3.60516
2011	-1.44713
2012	3.25696
2013	3.90892
2014	-0.86346
2015	8.38364
2016	-0.61741
2017	1.32859