Year	Percent
1961	8.66218
1962	0.01831
1963	-1.87732
1964	2.69073
1965	-2.05197
1966	1.71379
1967	2.40081
1968	1.67884
1969	-0.17987
1970	15.31566
1971	-9.21916
1972	1.20525
1973	10.20384
1974	16.04927
1975	11.83511
1976	18.90617
1977	16.89982
1978	3.081
1979	5.63864
1980	9.55072
1981	10.85308
1982	11.59255
1983	11.83804
1984	10.19072
1985	8.30578
1986	8.71172
1987	5.40195
1988	6.45562
1989	9.76901
1990	10.6372
1991	12.53196
1992	18.89723
1993	25.69848
1994	17.01641
1995	11.22107
1996	41.98877
1997	11.43522
1998	6.9314
1999	4.19394
2000	6.07985
2001	1.57312
2002	0.93321
2003	6.19731
2004	7.12684
2005	4.89965
2006	23.53013
2007	8.12949
2008	15.15117
2009	11.6373
2010	2.09168
2011	10.79791
2012	9.2065
2013	5.33183
2014	8.06829
2015	10.02498
2016	8.13362
2017	2.70108