Year	Percent
1970	0.64807
1971	0.6871
1972	0.47315
1973	0.56042
1974	0.8503
1975	0.36017
1976	0.49208
1977	0.55859
1978	0.54993
1979	1.14649
1980	0.15374
1981	0.09857
1982	-0.07459
1983	0.4047
1984	0.3495
1985	0.34185
1986	1.42797
1987	1.85243
1988	2.31918
1989	3.92867
1990	3.05886
1991	2.96305
1992	4.83269
1993	2.17044
1994	0.55703
1995	4.00701
1996	2.85263
1997	2.84605
1998	11.06872
1999	47.00347
2000	36.30093
2002	3.43899
2003	12.23913
2004	9.35114
2005	8.40152
2006	12.23473
2007	17.69575
2008	43.07353
2009	5.10607
2010	12.00425
2011	23.93127
2012	6.79976
2013	-4.51503
2014	-2.67077
2015	-2.88634
2016	6.1427
2017	-2.21976