Year	Percent
1970	0.50552
1971	0.53023
1972	0.2562
1973	0.08795
1974	-0.26578
1975	0.05587
1976	0.39664
1977	0.07235
1978	0.08884
1979	0.04674
1980	0.41151
1981	0.32933
1982	0.44951
1983	0.28381
1984	0.31696
1985	0.13325
1986	0.00282
1987	0.27372
1988	0.32935
1989	0.63485
1990	0.54713
1991	0.9833
1992	1.25321
1993	1.55255
1994	1.54736
1995	0.2367
1996	0.17704
1997	0.00912
1998	0.02839
1999	0.00637
2000	0.56808
2001	0.36452
2002	0.18742
2003	4.442
2004	1.31998
2005	2.59813
2006	3.44693
2007	3.55086
2008	2.66605
2009	2.12097
2010	1.3309
2011	2.48727
2012	2.89209
2013	3.14616
2014	3.20835
2015	3.23373
2016	2.23758
2017	2.42382