Year	Percent
1961	1.49229
1962	4.6064
1963	1.39578
1964	3.71836
1965	4.00702
1966	4.85464
1967	2.43983
1968	1.73975
1969	3.38982
1970	7.99087
1971	2.97507
1972	5.04661
1973	20.91038
1974	22.78045
1975	13.12001
1976	16.43449
1977	13.7544
1978	13.78805
1979	20.15071
1980	19.23945
1981	21.61203
1982	27.21275
1983	20.61221
1984	21.91845
1985	19.02595
1986	18.882
1987	15.25268
1988	16.67987
1989	14.49897
1990	20.6906
1991	19.78774
1992	14.79881
1993	14.42875
1994	11.18189
1995	9.79184
1996	7.6357
1997	6.55338
1998	5.10357
1999	3.62273
2000	1.59267
2001	3.47475
2002	3.34877
2003	3.45357
2004	3.06266
2005	2.24032
2006	3.49504
2007	3.42267
2008	4.34458
2009	2.56977
2010	0.67337
2011	0.79836
2012	-0.37039
2013	-2.3523
2014	-1.83209
2015	-1.02437
2016	-0.95631
2017	0.6695