Year	Percent
1962	1.95571
1963	3.68509
1964	4.95637
1965	2.37981
1966	0.55299
1967	6.64328
1968	3.32646
1969	5.58729
1970	8.85419
1971	7.62341
1972	9.15089
1973	14.26196
1974	11.61222
1975	4.45847
1976	9.63712
1977	3.85844
1978	8.12246
1979	17.75998
1980	15.74527
1981	10.61606
1982	9.68498
1983	4.60271
1984	9.64209
1985	5.36129
1986	3.77064
1987	8.61131
1988	8.80183
1989	12.5594
1990	7.56492
1991	9.14039
1992	9.89935
1993	8.61294
1994	6.32118
1995	4.13955
1996	5.88354
1997	5.76025
1998	1.21991
1999	-4.09568
2000	-3.39424
2001	-1.77402
2002	-3.40183
2003	-6.00773
2004	-3.59082
2005	-0.15015
2006	-0.53492
2007	3.13743
2008	1.28146
2009	-0.37551
2010	0.27064
2011	3.89789
2012	3.54481
2013	1.8125
2014	2.85027
2015	3.6435
2016	1.65798
2017	2.93102