Year	Percent
1960	2.05286
1961	2.21964
1962	2.36967
1963	2.50331
1964	2.59284
1965	2.63735
1966	2.70348
1967	2.74086
1968	2.72265
1969	2.60524
1970	2.43072
1971	2.23176
1972	2.06385
1973	1.99572
1974	2.04169
1975	2.17813
1976	2.34733
1977	2.48313
1978	2.54728
1979	2.54295
1980	2.47988
1981	2.3731
1982	2.31504
1983	2.31924
1984	2.41209
1985	2.56229
1986	2.7301
1987	2.85866
1988	2.88857
1989	2.78976
1990	2.61299
1991	2.17318
1992	0.56539
1993	0.45957
1994	0.46936
1995	0.53575
1996	0.62692
1997	0.68837
1998	0.67903
1999	0.58693
2000	0.43221
2001	-0.12855
2002	-3.43729
2003	-3.56459
2004	-3.59927
2005	-3.54298
2006	-3.47568
2007	-3.4306
2008	-3.47613
2009	-3.61046
2010	-3.14405
2011	0.72286
2012	0.57517
2013	0.5318
2014	0.54432
2015	0.6237
2016	0.68645
2017	0.7539