Year	Percent
1960	7.50674
1961	-17.45316
1962	-35.80702
1963	-18.12919
1964	6.62315
1965	12.95468
1966	14.64455
1967	21.91367
1968	35.2936
1969	42.44821
1970	25.10061
1971	22.69113
1972	24.61304
1973	22.99925
1974	15.42235
1975	5.50604
1976	3.50276
1977	-9.34602
1978	-6.77598
1979	-4.15198
1980	-0.05852
1981	3.20139
1982	-2.31499
1983	-2.30758
1984	5.30361
1985	7.28304
1986	11.29657
1997	-63.19703
1998	-28.55951
1999	-27.11634
2000	-7.56051
2001	2.55507
2002	11.57873
2003	0.19385
2004	-155.25595
2005	-152.18182
2006	-112.24628
2007	-161.42843
2008	-110.33592
2009	-79.68281
2010	-73.49627
2011	-72.65292
2012	-56.34111
2013	-61.83406
2014	-80.10432
2015	-87.07965
2016	-78.85769