Year	Percent
1960	2.66982
1961	2.42738
1962	2.94965
1963	2.54916
1964	2.06131
1965	1.55611
1966	1.44345
1967	1.63301
1968	1.6503
1969	1.50952
1970	1.10502
1971	0.72636
1972	0.83543
1973	0.81113
1974	0.61136
1975	0.02907
1976	-0.49884
1977	-0.26634
1978	0.08163
1979	0.27338
1980	0.46826
1981	0.53231
1982	0.50367
1983	0.34813
1984	0.27838
1985	0.36199
1986	0.43953
1987	0.54718
1988	0.6526
1989	0.72746
1990	0.94576
1991	1.17269
1992	1.02939
1993	0.83889
1994	0.72392
1995	0.59497
1996	0.36829
1997	0.16749
1998	0.22368
1999	0.40341
2000	0.48703
2001	0.62187
2002	0.79191
2003	0.77732
2004	0.72147
2005	0.67599
2006	0.66295
2007	0.92905
2008	1.30598
2009	1.28346
2010	1.0769
2011	1.14448
2012	1.09169
2013	1.17839
2014	1.24996
2015	1.16819
2016	1.12051
2017	1.13058