Year	Percent
1980	8.86798
1981	11.12048
1982	12.20456
1983	3.73112
1984	2.64215
1985	11.92922
1986	13.89736
1987	14.96785
1988	17.84355
1989	11.01397
1990	20.95069
1991	-10.63548
1992	-12.36005
1993	3.1453
1994	7.20837
1995	11.51678
1996	11.71163
1997	9.57149
1998	0.71824
1999	15.90279
2000	22.55218
2001	20.19523
2002	13.8278
2003	16.03455
2004	16.47297
2005	19.47457
2006	22.17336
2007	21.57401
2008	19.27221
2009	18.96746
2010	18.60224
2011	24.67652
2012	18.40553
2013	17.73619
2014	16.53685
2015	10.76618
2016	8.37923