Year	Percent
1960	2.54172
1961	1.85829
1962	1.72248
1963	1.67661
1964	1.76395
1965	1.90265
1966	2.11188
1967	2.22643
1968	2.1553
1969	1.85824
1970	1.82798
1971	2.70912
1972	2.22305
1973	1.97463
1974	2.02292
1975	2.3084
1976	2.64646
1977	2.90472
1978	2.95418
1979	2.71843
1980	2.29499
1981	2.26849
1982	3.28489
1983	2.8755
1984	2.60712
1985	2.42429
1986	2.23835
1987	2.06104
1988	1.97747
1989	2.02596
1990	2.17142
1991	2.0815
1992	0.31692
1993	0.47242
1994	0.36422
1995	0.1276
1996	-0.17955
1997	-0.41875
1998	-0.52318
1999	-0.41833
2000	-0.19333
2001	0.17138
2002	0.68914
2003	0.84669
2004	0.86959
2005	0.80471
2006	0.70756
2007	0.65017
2008	0.61679
2009	0.65857
2010	0.7283
2011	0.82094
2012	0.88502
2013	0.92532
2014	0.95254
2015	0.95534
2016	0.95214
2017	0.94701