Year	Percent
1960	1.3333
1961	1.38748
1962	1.44109
1963	1.48702
1964	1.52228
1965	1.55203
1966	1.57879
1967	1.61376
1968	1.67142
1969	1.75757
1970	1.86143
1971	1.96842
1972	2.06365
1973	2.14268
1974	2.20098
1975	2.2431
1976	2.28116
1977	2.31849
1978	2.34759
1979	2.36842
1980	2.38335
1981	2.34453
1982	2.29893
1983	2.33681
1984	2.4827
1985	2.66939
1986	2.92781
1987	3.07633
1988	2.89031
1989	2.29667
1990	1.46651
1991	0.57791
1992	-0.13629
1993	-0.55641
1994	-0.55123
1995	-0.20569
1996	0.17602
1997	0.53809
1998	1.11308
1999	1.91458
2000	2.81051
2001	3.75927
2002	4.49871
2003	4.77276
2004	4.51511
2005	3.94145
2006	3.30806
2007	2.81076
2008	2.46228
2009	2.32284
2010	2.32543
2011	2.34084
2012	2.30857
2013	2.27909
2014	2.24394
2015	2.20547
2016	2.17548
2017	2.15373