Year	Percent
1967	8.54972
1968	-8.68602
1969	7.12847
1970	9.06914
1971	5.16336
1972	3.15678
1973	-1.04551
1974	20.93723
1975	13.04859
1976	11.69319
1977	22.5954
1978	6.46036
1979	10.59694
1980	-0.17758
1981	1.56353
1982	14.48742
1983	2.68309
1984	9.00161
1985	39.41911
1986	40.51679
1987	18.49801
1988	9.70615
1989	13.73657
1990	11.96453
1991	134.03587
1992	1.95003
1993	5.14232
1994	3.7774
1995	3.96325
1996	8.36857
1997	-5.96912
1998	5.41182
1999	-2.43549
2000	2.21698
2001	1.80544
2002	10.39134
2003	12.89394
2004	16.84634
2005	3.59331
2006	1.93222
2007	4.29567
2008	2.01075
2009	5.17913
2010	4.29871
2011	3.71584
2012	4.45137
2013	5.6722
2014	6.61993
2015	6.37376
2016	7.14046
2017	8.13655