Year	Percent
1970	-1.47551
1971	-1.74562
1972	-1.64841
1973	-1.01298
1974	-0.50038
1975	-1.71039
1976	-2.25465
1977	-2.17156
1978	-1.93335
1979	-3.60814
1980	-4.64925
1981	-3.95004
1982	-2.68039
1983	-3.026
1984	-2.82553
1985	-2.06978
1986	-0.39465
1987	-0.34687
1988	-0.37034
1989	-0.643
1990	-0.21719
1991	-0.51488
1992	-0.52262
1993	0.06451
1994	0.19707
1995	0.46817
1996	0.82048
1997	1.18291
1998	1.32388
1999	0.71302
2000	0.26908
2001	1.76356
2002	4.37507
2003	3.66383
2004	5.04074
2005	5.05972
2006	5.29853
2007	6.64929
2008	5.97485
2009	4.93936
2010	5.19767
2011	4.88861
2012	6.09033
2013	5.95933
2014	6.92294
2015	7.99389
2016	7.97122
2017	7.57397