Year	Percent
1970	-0.01555
1971	0.29143
1972	0.05114
1973	0.58813
1974	0.94869
1975	0.76541
1976	0.89779
1977	1.06881
1978	0.44481
1979	0.02545
1980	-0.32665
1981	0.48252
1982	0.04308
1983	0.31615
1984	0.02865
1985	0.03904
1986	0.4252
1987	0.92481
1988	2.47061
1989	1.32237
1990	1.19608
1991	1.19777
1992	0.43038
1993	2.27707
1994	2.48266
1995	1.99406
1996	1.83106
1997	1.48401
1998	3.16728
1999	1.5025
2000	1.83521
2001	0.99656
2002	2.17435
2003	0.58636
2004	0.64791
2005	1.61441
2006	2.21537
2007	1.95416
2008	0.76927
2009	1.2265
2010	0.53629
2011	0.89548
2012	1.28569
2013	1.37486
2014	2.01683
2015	1.92611
2016	2.71559
2017	3.20712