Year	Percent
1970	17.68494
1971	-9.94311
1972	5.60992
1973	19.34009
1974	11.8512
1975	31.23716
1976	13.9389
1977	25.3265
1978	20.17315
1979	5.06223
1980	8.41454
1981	34.01596
1982	4.02809
1983	5.96326
1984	4.26646
1985	-1.90298
1986	-1.96203
1987	3.95765
1988	27.94472
1989	83.4338
1990	58.59521
1991	2.41667
1992	-4.85459
1993	-33.42893
1994	13.14675
1995	3.41246
1996	-82.8921
1997	72.2609
1998	52.92269
1999	58.00362
2000	3.93147
2001	1.59309
2002	0.51565
2003	89.47596
2004	15.87355
2005	15.05493
2006	17.85621
2007	17.81229
2008	33.3556
2009	11.06382
2010	159.71885
2011	134.98168
2012	133.10177
2013	102.68047
2014	24.93149
2015	11.43952
2016	14.83578
2017	11.48485