Year	Percent
1975	3.69452
1976	5.62409
1977	5.63477
1978	5.91542
1979	5.47313
1980	3.94434
1981	3.75113
1982	3.31231
1983	3.16418
1984	2.31259
1985	2.38454
1986	1.49865
1987	1.40262
1988	1.45246
1989	1.52843
1990	2.26458
1991	1.41799
1992	1.55438
1993	1.266
1994	1.01235
1995	2.47423
1996	2.3612
1997	5.69629
1998	3.33605
1999	7.65988
2000	8.39485
2001	8.94024
2002	9.49754
2003	6.23005
2004	6.42187
2005	6.21272
2006	9.17673
2007	9.53362
2008	8.39798
2009	10.91094
2010	53.19095
2011	-43.46255
2012	198.07448
2013	-25.0167
2014	-3.22935
2015	41.20066
2016	12.93614
2017	48.55098