Year	Percent
1975	1.05247
1976	1.01848
1977	1.04046
1978	0.999
1979	1.07526
1980	0.81311
1981	0.95614
1982	1.03308
1983	0.79142
1984	0.76259
1985	0.64635
1986	0.12867
1987	0.39751
1988	0.84868
1989	0.26575
1990	0.21409
1991	0.18296
1992	0.51448
1993	0.29511
1994	0.55043
1995	0.63161
1996	1.31699
1997	2.22487
1998	3.69482
1999	4.76752
2000	5.03413
2001	4.15213
2002	3.26532
2003	1.81312
2004	2.71638
2005	1.7339
2006	1.74949
2007	3.19089
2008	2.99066
2009	1.88846
2010	4.0044
2011	3.86659
2012	3.51318
2013	2.8181
2014	3.95683
2015	4.1459
2016	4.3364
2017	3.43882