Year	Percent
1961	10.27172
1962	0.9304
1963	9.72833
1964	7.86649
1965	8.88213
1966	5.31893
1967	4.62587
1968	5.97248
1969	9.49887
1970	7.70521
1971	7.37433
1972	9.44639
1973	7.60261
1974	-6.78209
1975	5.37306
1976	5.20508
1977	1.6103
1978	5.86527
1979	2.00246
1980	-0.3069
1981	-2.43246
1982	-1.74025
1983	-1.6524
1984	1.50367
1985	2.1123
1986	0.18574
1987	-2.58512
1988	3.90978
1989	3.25973
1990	-1.05223
1991	1.86983
1992	-0.0663
1993	-2.17715
1994	1.49056
1995	1.62383
1996	2.40984
1997	3.97008
1998	3.3207
1999	2.6781
2000	3.49556
2001	3.59165
2002	3.54262
2003	5.54236
2004	4.80138
2005	0.30457
2006	5.3356
2007	3.01098
2008	-0.59939
2009	-4.55212
2010	-5.60078
2011	-8.99796
2012	-6.79786
2013	-2.53726
2014	1.41306
2015	0.36821
2016	0.17145
2017	1.49779