Year	Percent
1961	0.53493
1962	0.57162
1963	2.11646
1964	2.82429
1965	0.62006
1966	1.27763
1967	2.58867
1968	0.56412
1969	1.20819
1970	3.42244
1971	2.90334
1972	4.99802
1973	8.54223
1974	11.61138
1975	9.38283
1976	4.53451
1977	4.6568
1978	7.92136
1979	9.24522
1980	10.1405
1981	3.64217
1982	4.87168
1983	7.49696
1984	1.62926
1985	0.80957
1986	0.33845
1987	2.2893
1988	-0.19193
1989	-1.27656
1990	0.56521
1991	0.4928
1992	5.06106
1993	3.55471
1994	3.67975
1995	0.46671
1996	-0.94238
1997	1.60884
1998	0.99752
1999	0.84239
2000	-1.24818
2001	1.02821
2002	1.67134
2003	1.13136
2004	1.965
2005	1.74832
2006	1.96998
2007	4.82494
2008	7.5275
2009	6.47096
2010	2.59015
2011	5.8441
2012	6.17573
2013	5.5048
2014	4.19762
2015	3.05617
2016	1.39518
2017	1.51034