Year	Percent
1960	1.54378
1961	-0.45112
1962	0.94586
1963	1.70933
1964	5.94039
1965	5.94595
1966	0.16558
1967	0
1968	-0.82303
1969	0.6046
1970	11.73184
1971	13.98658
1972	0.82956
1973	1.1794
1974	14.28571
1975	1.62197
1976	-0.51453
1977	0.33324
1978	14.8368
1979	21.08284
1980	33.09002
1981	22.66794
1982	21.92783
1983	17.78225
1984	18.89217
1985	5.29157
1986	-19.51302
1987	-2.52459
1988	-5.06085
1989	4.59753
1990	15.17956
1991	13.99198
1992	12.28226
1993	14.24619
1994	23.42459
1995	23.6393
1996	29.65559
1997	24.07176
1998	-1.16208
1999	21.49356
2000	36.36242
2001	24.91185
2002	20.45872
2003	23.55626
2004	28.31077
2005	36.06775
2006	32.49422
2007	31.92473
2008	35.40055
2009	20.83906
2010	26.16888
2011	32.99035
2012	29.55798
2013	24.08032
2014	15.52129
2015	18.01846
2016	17.09263
2017	16.98916