Year	Percent
1960	2.83863
1961	2.78531
1962	2.61533
1963	2.58984
1964	2.56746
1965	2.4886
1966	2.66588
1967	2.91521
1968	2.61194
1969	2.29985
1970	2.43885
1971	2.26742
1972	2.17515
1973	2.06426
1974	2.12352
1975	2.43672
1976	2.38366
1977	2.326
1978	2.49011
1979	2.2068
1980	2.244
1981	2.30413
1982	1.96084
1983	1.81968
1984	1.77107
1985	1.88898
1986	1.88735
1987	1.80547
1988	1.86461
1989	1.81838
1990	1.52303
1991	0.4622
1992	-0.35426
1993	-0.41865
1994	-0.42687
1995	-0.48646
1996	-0.57309
1997	-0.57367
1998	-0.49169
1999	-0.44439
2000	-0.41957
2001	-1.68261
2002	-1.96698
2003	-0.47148
2004	-0.32251
2005	-0.37087
2006	-0.34634
2007	-1.23177
2008	-1.42152
2009	-0.58884
2010	-0.3503
2011	-0.2488
2012	-0.41923
2013	-0.4399
2014	-0.44319
2015	-0.49486
2016	-0.54853
2017	-0.52268