Year	Percent
1977	1.77903
1978	2.09534
1979	1.69501
1980	1.40505
1981	1.47662
1982	0.88448
1983	0.49724
1984	0.40127
1985	0.63569
1986	0.95133
1987	2.12015
1988	4.20705
1989	0.90599
1990	0.62352
1991	0.96427
1992	0.90127
1993	1.25001
1994	0.50219
1995	0.51312
1996	0.4906
1997	0.47442
1998	3.46885
1999	0.84396
2000	-4.08838
2001	-5.00724
2002	-4.8949
2003	0.08892
2004	1.34111
2005	1.98446
2006	2.10147
2007	2.51868
2008	1.91918
2009	1.84569
2010	2.04554
2011	2.39149
2012	2.50779
2013	2.51275
2014	1.98522
2015	1.84345
2016	1.71051
2017	1.36842