Year	Percent
1976	21.24487
1977	16.34798
1978	7.37835
1979	9.05435
1980	4.61064
1981	0.82883
1982	4.77451
1983	4.71504
1984	7.35776
1985	3.61524
1986	2.52141
1987	5.90727
1988	7.50079
1989	6.41951
1990	5.13997
1991	-1.83474
1992	6.52783
1993	-1.70263
1994	3.7322
1995	6.51936
1996	-0.26929
1997	1.122
1998	3.95312
1999	3.66207
2000	4.6058
2001	2.49
2002	2.22091
2003	1.23798
2004	3.18083
2005	2.24122
2006	2.78102
2007	2.61259
2008	1.28833
2009	-4.37427
2010	-1.2976
2011	-2.20605
2012	-4.52416
2013	-5.71504
2014	-0.31256
2015	2.56134
2016	2.56077
2017	3.45829