Year	Percent
1961	0.60898
1962	1.40252
1963	-0.96927
1964	3.14074
1965	7.95093
1966	2.48288
1967	-3.59822
1968	3.29113
1969	6.49423
1970	6.83129
1971	3.35926
1972	14.72537
1973	15.99745
1974	29.64571
1975	24.31865
1976	7.91145
1977	-0.03203
1978	4.43188
1979	8.14135
1980	17.3117
1981	0.97821
1982	12.10857
1983	6.82635
1984	3.0075
1985	8.22348
1986	3.04347
1987	7.34001
1988	7.32802
1989	2.8483
1990	6.67947
1991	5.99313
1992	6.26513
1993	7.23674
1994	0.84161
1995	1.1569
1996	2.89599
1997	3.45061
1998	7.48758
1999	6.81109
2000	-4.66653
2001	3.36107
2002	3.31902
2003	7.87383
2004	2.23911
2005	6.81774
2006	3.72511
2007	2.95506
2008	1.35599
2009	1.39069
2010	4.22979
2011	9.39134
2012	3.57651
2013	3.6213
2014	3.85266
2015	4.12739
2016	6.53505
2017	2.99473