Year	Percent
1961	7.12471
1962	-7.97133
1963	13.55123
1964	16.025
1965	6.96386
1966	36.85927
1967	36.96647
1968	0.84849
1969	-1.28413
1970	9.93641
1971	-0.11387
1972	1.84633
1973	3.91625
1974	15.90691
1975	87.96915
1976	-1.89109
1977	13.51147
1978	3.66474
1979	6.06529
1980	3.06478
1981	7.7107
1982	4.88318
1983	2.44921
1984	16.85669
1985	4.56413
1986	-7.02173
1987	0.66528
1988	2.22538
1989	5.29709
1990	13.46147
1991	14.97894
1992	7.28328
1993	13.8705
1994	17.1913
1995	51.26658
1996	10.92142
1997	15.6215
1998	2.2282
1999	-6.35094
2000	2.78159
2001	1.14646
2002	-5.03611
2003	21.7917
2004	13.10062
2005	9.13475
2006	10.57956
2007	11.75587
2008	14.28769
2009	8.24934
2010	2.60657
2011	8.35031
2012	5.25991
2013	4.51439
2014	3.05052
2015	0.28574
2016	5.49538
2017	7.31517