Year	Percent
1960	4.42027
1961	4.57057
1962	4.69377
1963	4.74622
1964	4.72619
1965	4.64422
1966	4.55864
1967	4.48435
1968	4.40437
1969	4.31422
1970	3.38331
1971	2.30358
1972	2.22394
1973	2.16898
1974	2.11869
1975	2.091
1976	2.06069
1977	2.0437
1978	2.0471
1979	2.13819
1980	2.26391
1981	2.29395
1982	2.30422
1983	2.3492
1984	2.42822
1985	2.50993
1986	2.61049
1987	2.65598
1988	2.55709
1989	1.76083
1990	0.77358
1991	0.37944
1992	0.04829
1993	-0.19216
1994	-0.33485
1995	-0.38294
1996	-0.42338
1997	-0.45693
1998	-0.44758
1999	-0.38877
2000	0.67077
2001	1.77622
2002	1.89513
2003	1.99138
2004	2.04999
2005	2.09112
2006	2.12073
2007	2.15312
2008	2.18356
2009	2.21418
2010	2.2414
2011	2.25934
2012	2.35621
2013	2.42566
2014	2.48416
2015	2.52451
2016	2.56268
2017	2.5981