Year	Percent
1960	1.9004
1961	0.15099
1962	0.4132
1963	-0.67991
1964	-2.07357
1965	-0.17489
1966	-0.90586
1967	-0.42445
1968	0.44502
1969	0.28448
1970	-0.01089
1971	1.59707
1972	4.20079
1973	4.84358
1974	4.9194
1975	4.71291
1976	4.52081
1977	2.38333
1978	1.45387
1979	1.34554
1980	1.19236
1981	5.12139
1982	5.50949
1983	4.57079
1984	6.47918
1985	5.55402
1986	4.63213
1987	3.41132
1988	3.67997
1989	4.23098
1990	5.00295
1991	5.31892
1992	4.9555
1993	6.48845
1994	6.73422
1995	6.84605
1996	6.16253
1997	6.48042
1998	6.12383
1999	5.3445
2000	6.53393
2001	6.66043
2002	6.79109
2003	6.76396
2004	7.92344
2005	8.67929
2006	8.73204
2007	8.82533
2008	8.62659
2009	7.32843
2010	8.36294
2011	8.53967
2012	9.60159
2013	10.69601
2014	10.84225
2015	10.55443
2016	11.00818
2017	11.68109