Year	Percent
1960	5.66589
1961	5.654
1962	5.65644
1963	5.65238
1964	5.66484
1965	5.66911
1966	5.68122
1967	5.69392
1968	5.71627
1969	5.72945
1970	5.76018
1971	5.78258
1972	5.80711
1973	5.82572
1974	5.87116
1975	5.92314
1976	5.88044
1977	5.80187
1978	5.83207
1979	5.97706
1980	6.15122
1981	6.38905
1982	6.48475
1983	6.14713
1984	6.84065
1985	7.71708
1986	6.33958
1987	5.15335
1988	4.18695
1989	3.52369
1990	3.19807
1991	2.76836
1992	-7.11528
1993	-6.7438
1994	-5.36867
1995	-3.40009
1996	-1.21983
1997	8.14551
1998	8.63645
1999	7.72504
2000	6.11708
2001	4.39778
2002	3.13694
2003	2.4887
2004	2.67053
2005	3.38713
2006	4.20031
2007	4.72374
2008	4.92043
2009	4.73024
2010	4.29373
2011	3.83597
2012	3.50609
2013	3.29772
2014	3.24505
2015	3.3023
2016	3.37375
2017	3.40475