Year	Percent
1961	6.68482
1962	8.42128
1963	1.55306
1964	2.24769
1965	2.59365
1966	3.33306
1967	-1.90391
1968	1.06948
1969	2.66126
1970	1.39599
1971	5.16242
1972	7.36898
1973	18.86405
1974	24.45487
1975	5.46622
1976	5.99796
1977	11.31773
1978	9.70619
1979	19.24574
1980	16.91728
1981	16.75927
1982	6.27721
1983	14.43583
1984	26.07208
1985	26.1777
1986	29.70502
1987	31.82108
1988	28.28772
1989	32.48345
1990	38.4505
1991	27.68834
1992	14.08292
1993	12.22003
1994	12.57337
1995	11.07643
1996	11.42145
1997	3.41099
1998	13.29685
1999	7.86049
2000	11.74339
2001	11.03306
2002	14.94457
2003	12.21097
2004	8.98597
2005	10.07531
2006	6.08268
2007	9.76607
2008	9.33571
2009	2.04314
2010	6.10026
2011	6.20506
2012	4.74734
2013	0.84119
2014	5.13903
2015	0.08726
2016	5.27924
2017	5.5413