Year	Percent
1960	10.93823
1961	13.35784
1962	14.07963
1963	15.19172
1964	10.83206
1965	8.83133
1966	9.26134
1967	8.72094
1968	5.11837
1969	4.0111
1970	4.01682
1971	5.56399
1972	2.90063
1973	8.32364
1974	21.97208
1975	6.90151
1976	0.74632
1977	-6.81576
1978	-11.1488
1979	1.29397
1980	6.95099
1981	4.92686
1982	-2.6161
1983	8.30947
1984	8.03271
1985	6.05241
1986	-0.42734
1987	-1.93454
1988	-6.66167
1989	13.03555
1990	19.26593
1991	5.12637
1992	-2.55574
1993	-0.22285
1994	8.56406
1995	5.29115
1996	15.1869
1997	7.27298
1998	-1.75842
1999	3.75319
2000	11.63122
2001	3.33
2002	12.29143
2003	17.12977
2004	17.02925
2005	19.18998
2006	14.37165
2007	6.06198
2008	9.81433
2009	-2.37789
2010	10.92392
2011	10.24791
2012	1.93846
2013	-4.7478
2014	-14.70316