Year	Percent
1974	-0.11116
1975	0.62278
1976	0.38947
1977	0.53309
1978	0.68152
1979	1.2525
1980	0.22603
1981	-0.12768
1982	0.47529
1983	0.68248
1984	0.61615
1985	0.7556
1986	0.78771
1987	0.93076
1988	1.21651
1989	1.4312
1990	1.42675
1991	1.69793
1992	1.39202
1993	0.7668
1994	1.01388
1995	1.27843
1996	2.25333
1997	2.60551
1998	1.90304
1999	4.4169
2000	4.92683
2001	4.09506
2002	3.69533
2003	4.79304
2004	6.75225
2005	6.21441
2006	6.61879
2007	7.87688
2008	8.70793
2009	3.38987
2010	3.83461
2011	5.8868
2012	5.83609
2013	5.77863
2014	8.62901
2015	6.27595
2016	5.29955
2017	5.50331