Year	Percent
1977	0.4444
1978	0.27
1979	0.19682
1985	0.00371
1986	0.00656
1987	0.03676
1988	0.05507
1989	0.00616
1990	0.04307
1991	0.07044
1992	0.09624
1993	0.07304
1994	0.06714
1995	0.0375
1996	0.07018
1997	0.02199
1998	-0.00971
1999	-0.01078
2000	0.1506
2001	0.24596
2002	0.06707
2003	0.02423
2004	0.05186
2005	0.11888
2006	0.65686
2007	0.79956
2008	0.34152
2009	0.51565
2010	0.62218
2011	0.24467
2012	0.36591
2013	0.41629
2014	0.39244
2015	0.65272
2016	0.61359
2017	0.87188