Year	Percent
1971	2.26645
1972	4.91886
1973	3.05522
1974	2.5472
1975	3.93244
1976	-0.1239
1977	6.75571
1978	5.67669
1979	1.70891
1980	1.89987
1981	2.1223
1982	1.32102
1983	-0.94901
1984	3.70968
1985	2.92073
1986	-0.47356
1987	4.65224
1988	5.66838
1989	6.23404
1990	8.37501
1991	1.3453
1992	2.64061
1993	2.18059
1994	5.33977
1995	9.07377
1996	6.95958
1997	9.18947
1998	7.37434
1999	9.37786
2000	8.1091
2001	4.13242
2002	4.53281
2003	1.45335
2004	4.74848
2005	3.7218
2006	2.7148
2007	2.21072
2008	-5.87457
2009	-5.59054
2010	1.24849
2011	2.5368
2012	-0.38585
2013	1.10507
2014	7.53938
2015	24.37653
2016	3.96126
2017	6.49734