Year	Percent
1961	3.47172
1962	2.35128
1963	0.54933
1964	1.69518
1965	1.50133
1966	1.81781
1967	1.31204
1968	3.14206
1969	1.92108
1970	4.94045
1971	17.15196
1972	-4.60646
1973	9.62761
1974	48.89659
1975	5.91402
1976	10.84059
1977	11.9271
1978	10.08512
1979	13.98784
1980	25.86204
1981	14.354
1982	1.93979
1983	6.8048
1984	8.43351
1985	4.97253
1986	2.40534
1987	8.84202
1988	9.06096
1989	16.01137
1990	30.2596
1991	53.7886
1992	21.92611
1993	13.62442
1994	29.07765
1995	28.57704
1996	24.0219
1997	7.00196
1998	-3.13109
1999	10.85632
2000	22.65477
2001	-0.48151
2002	1.31149
2003	8.32884
2004	12.24588
2005	16.11682
2006	10.56356
2007	6.42326
2008	15.35548
2009	-11.18979
2010	16.08172
2011	18.24091
2012	7.48134
2013	-0.06184
2014	-0.29013
2015	-6.57198
2016	0.8899
2017	6.80018