Year	Percent
1960	1.67536
1961	1.75005
1962	1.79652
1963	1.86197
1964	1.90275
1965	1.95258
1966	2.01199
1967	2.04547
1968	2.09999
1969	2.14056
1970	2.16972
1971	2.22183
1972	2.251
1973	2.30417
1974	2.33406
1975	2.38816
1976	2.39078
1977	2.37868
1978	2.45806
1979	2.61327
1980	2.788
1981	2.98224
1982	3.0698
1983	5.57296
1984	8.99895
1985	8.53442
1986	8.16935
1987	7.81833
1988	7.3086
1989	6.5539
1990	5.73094
1991	4.73712
1992	3.91608
1993	2.71313
1994	-0.29951
1995	1.29442
1996	3.16006
1997	4.69362
1998	5.57906
1999	5.67234
2000	5.27776
2001	4.77727
2002	4.47191
2003	4.36028
2004	4.52029
2005	4.80854
2006	5.10758
2007	5.2538
2008	5.2577
2009	5.13368
2010	4.91266
2011	4.67955
2012	4.49498
2013	4.34771
2014	4.25276
2015	4.20598
2016	4.15661
2017	4.10323