Year	Percent
1975	1.77352
1976	0.9605
1977	0.23389
1978	1.05452
1979	0.81752
1980	0.93028
1981	0.38841
1982	0.62736
1983	0.54878
1984	0.31778
1985	0.41789
1986	0.77249
1987	0.8675
1988	0.50418
1989	0.18955
1990	0.44568
1991	0.1554
1992	-2.06971
1993	0.79578
1994	0.9381
1995	1.92254
1996	2.21744
1997	3.5429
1998	3.01311
1999	2.61522
2000	2.18999
2001	2.43626
2002	1.72212
2003	1.08024
2004	1.70939
2005	2.04227
2006	1.96986
2007	2.17864
2008	1.92566
2009	1.63127
2010	1.43912
2011	1.18817
2012	1.2214
2013	1.30296
2014	1.24043
2015	1.49105
2016	1.58758
2017	1.67048