Year	Percent
1977	0.39806
1978	-0.07705
1979	1.34429
1980	4.7355
1981	5.80574
1982	6.35381
1983	1.34037
1984	-2.19136
1985	1.02881
1986	0.29862
1987	-8.15066
1988	-10.08168
1989	0.87016
1990	2.10601
1991	1.53364
1992	1.79674
1993	1.93109
1994	4.28711
1995	2.32927
1996	4.20952
1997	12.16882
1998	10.39352
1999	6.22905
2000	6.72783
2001	4.85362
2002	1.9016
2003	7.67198
2004	8.51174
2005	6.74468
2006	16.22949
2007	10.44328
2008	9.50076
2009	4.00308
2010	8.65854
2011	12.67247
2012	8.36488
2013	8.33114
2014	9.98448
2015	9.31167
2016	10.36753
2017	9.80867