Year	Percent
1960	1.18431
1961	1.18457
1962	1.19167
1963	1.19845
1964	1.20474
1965	1.21025
1966	1.215
1967	1.21899
1968	1.22233
1969	1.22503
1970	1.22727
1971	1.22975
1972	1.25974
1973	1.28984
1974	1.3203
1975	1.35108
1976	1.3823
1977	1.41372
1978	1.44563
1979	1.47795
1980	1.51081
1981	1.54435
1982	1.59948
1983	1.65653
1984	1.71606
1985	1.77796
1986	1.84313
1987	1.91132
1988	1.9817
1989	2.05229
1990	2.12259
1991	2.19144
1992	2.2349
1993	2.27847
1994	2.32489
1995	2.37572
1996	2.43179
1997	2.49247
1998	2.55827
1999	2.6288
2000	2.70413
2001	2.78337
2002	2.84954
2003	2.92044
2004	2.997
2005	3.0792
2006	3.16808
2007	3.26321
2008	3.36342
2009	3.46612
2010	3.57028
2011	3.67502
2012	3.78073
2013	3.88826
2014	3.99906
2015	4.11431
2016	4.23441
2017	4.3592