Year	Percent
1961	2.27481
1962	4.38533
1963	4.8067
1964	3.66809
1965	4.98115
1966	7.84772
1967	5.43451
1968	4.97584
1969	3.46996
1970	8.21201
1971	1.91135
1972	1.34981
1973	7.20923
1974	1.69488
1975	2.30388
1976	6.67625
1977	7.29827
1978	7.84955
1979	3.12669
1980	3.01389
1981	3.82065
1982	3.36354
1983	3.65152
1984	3.84488
1985	2.77035
1986	3.6321
1987	7.55455
1988	11.33247
1989	10.41546
1990	9.61956
1991	7.2774
1992	7.0005
1993	7.27358
1994	7.01272
1995	7.04777
1996	4.49368
1997	-3.89126
1998	-8.73405
1999	3.38173
2000	3.37497
2001	2.49141
2002	5.2711
2003	6.38935
2004	5.55791
2005	3.51384
2006	4.33213
2007	4.84345
2008	1.19042
2009	-1.1898
2010	6.99058
2011	0.36014
2012	6.74668
2013	2.23668
2014	0.58042
2015	2.65881
2016	2.97385
2017	3.6411