Year	Percent
1971	0.28985
1972	6.58108
1973	-1.76987
1974	-3.45863
1975	-5.39426
1976	-4.0314
1977	2.07858
1978	0.51299
1979	8.58449
1980	6.03673
1981	2.73198
1982	-4.97414
1983	5.69752
1984	3.32127
1985	-2.53986
1986	1.9119
1987	7.36494
1988	1.52382
1989	7.04489
2003	-0.33043
2004	2.97667
2005	3.64469
2006	3.70518
2007	4.06618
2008	0.88583
2009	-6.64666
2010	0.94788
2011	-8.10248
2012	-14.93992
2013	-5.67244
2014	-0.81527
2015	0.35616