Year	Percent
1970	0.16983
1971	0.27246
1972	0.63704
1973	0.3189
1974	0.02342
1975	0.19472
1976	0.14255
1977	0.32393
1978	0.05503
1979	0.23785
1980	0.27507
1981	0.2243
1982	0.13527
1983	0.24754
1984	0.48873
1985	0.48906
1986	0.74303
1987	0.56539
1988	0.62351
1989	1.83775
1990	1.07216
1991	1.33021
1992	1.46228
1993	0.95883
1994	2.66504
1995	1.60463
1996	1.33797
1997	2.50943
1998	2.38124
1999	10.01268
2000	17.28888
2001	7.98193
2002	1.48328
2003	0.39262
2004	-3.95028
2005	6.41607
2006	2.82782
2007	5.4261
2008	5.30502
2009	1.91797
2010	-0.17821
2011	3.81479
2012	-3.3436
2013	2.03977
2014	2.81014
2015	2.40869
2016	5.72318
2017	4.09676