Year	Percent
1960	88.71121
1961	89.01088
1962	81.78586
1963	79.50809
1964	80.63048
1965	83.00137
1966	79.46323
1967	80.76703
1968	82.82835
1969	86.70252
1970	88.06704
1971	87.33537
1972	82.12118
1973	88.51089
1974	101.69206
1975	91.62476
1976	87.31501
1977	86.06129
1978	83.0064
1979	90.08842
1980	87.70724
1981	85.85086
1982	88.18606
1983	89.40868
1984	100.16247
1985	107.46002
1986	98.34069
1987	95.60288
1988	97.13807
1989	99.86154
1990	97.80076
1991	97.69554
1992	96.70786
1993	96.96897
1994	100.18098
1995	102.47531
1996	106.52428
1997	115.847
1998	126.17854
1999	130.82962
2000	148.48491
2001	147.43946
2002	141.96461
2003	138.90023
2004	153.03574
2005	161.67641
2006	176.24689
2007	182.888
2008	187.11188
2009	164.06951
2010	174.52309
2011	177.98966
2012	186.44431
2013	190.62858
2014	208.23038
2015	222.70321
2016	221.26778
2017	230.01643