Year	Percent
1961	0.1165
1962	13.27821
1963	8.5869
1964	6.22102
1965	0.20294
1966	-2.34583
1967	8.708
1968	-2.37477
1969	-0.51188
1970	0.09654
1971	2.98015
1972	-2.23205
1973	23.7721
1974	8.54888
1975	-15.52639
1976	8.31103
1977	18.68272
1978	15.21914
1979	0.20919
1980	-5.22828
1981	-1.82121
1982	1.90475
1983	-0.40673
1984	3.20989
1985	0.52067
1986	2.75366
1987	-0.96063
1988	6.86444
1989	4.06603
1990	4.19979
1991	4.96545
1992	4.86461
1993	1.48622
1994	4.02853
1995	1.58432
1996	4.06596
1997	2.37584
1998	0.38189
1999	-0.56803
2000	2.86542
2001	2.61402
2002	-0.14224
2003	3.6993
2004	0.87036
2005	2.62679
2006	3.37538
2007	3.95375
2008	5.7979
2009	1.17896
2010	4.96264
2011	5.67833
2012	4.69146
2013	0.52354
2014	1.75573
2015	1.15608
2016	1.04154
2017	4.19528