Year	Percent
1978	0.02532
1979	0.01432
1980	0.00937
1981	0.0067
1982	0.00582
1983	0.00358
1984	0.00139
1985	0.00221
1986	0.00247
1987	0.33628
1988	0.03914
1989	0.06874
1990	0.16425
1991	0.1701
1992	0.13149
1993	0.18084
1994	0.33612
1995	0.52314
1996	0.50876
1997	0.38606
1998	0.11446
1999	0.27295
2000	-0.01818
2001	0.35554
2002	0.12713
2003	0.40904
2004	0.04434
2005	0.29127
2006	0.46932
2007	0.58835
2008	0.80296
2009	2.12853
2010	2.38382
2011	1.93511
2012	3.58704
2013	2.88378
2014	1.40958
2015	1.24341
2016	3.25656
2017	4.4576