Year	Percent
1961	20.07744
1962	-3.56742
1963	4.68715
1964	5.41722
1965	-1.02936
1966	3.15203
1967	-5.31799
1968	3.05681
1969	5.36188
1970	5.18451
1971	1.38022
1972	4.29081
1973	5.51044
1974	12.45518
1975	21.08691
1976	8.07495
1977	14.30413
1978	12.50771
1979	26.13071
1980	16.38402
1981	-6.06332
1982	5.67202
1983	6.42855
1984	17.21619
1985	5.06884
1986	-4.25741
1987	-3.4178
1988	3.49122
1989	14.75718
1990	5.98556
1991	4.09314
1992	5.40176
1993	7.74265
1994	6.63845
1995	16.10271
1996	14.45311
1997	32.39779
1998	11.45056
1999	14.95414
2000	38.94489
2001	13.71641
2002	1.02786
2003	11.94575
2004	13.14616
2005	18.85693
2006	2.84513
2007	6.90188
2008	23.99094
2009	8.24735
2010	12.3033
2011	14.29434
2012	15.4165
2013	13.16338
2014	8.3034
2015	4.85689
2016	3.80473
2017	20.22556