Year	Percent
1976	-61.89253
1977	-53.7277
1978	-49.86937
1979	-49.15697
1980	-52.68426
1981	-49.13842
1982	-55.84379
1983	-46.01017
1984	-40.93802
1985	-41.91452
1986	-41.92959
1987	-36.52301
1988	-44.84967
1989	-42.80283
1990	-35.19262
1991	-32.93546
1992	-33.0995
1993	-39.49487
1994	-31.98711
1995	-35.35808
1996	-47.53432
1997	-40.3557
1998	-42.853
1999	-46.32752
2000	-6.43127
2001	-19.80858
2002	-7.51796
2003	2.36594
2004	-7.5532
2005	-21.70576
2006	-16.16293
2007	-1.18751
2008	-10.7341
2009	-9.0344
2010	-14.28304
2011	-15.61887
2012	-17.82029
2013	-7.83195
2014	-15.99428