Year	Percent
1970	66.3545
1971	69.53164
1972	68.88049
1973	71.49138
1974	68.11018
1976	69.35129
1977	70.24304
1978	69.23204
1979	70.49628
1980	72.64696
1985	87.00433
1986	88.00467
1987	91.7698
1988	92.10325
1989	92.85689
1990	94.47892
1991	94.86622
1992	92.74115
1993	94.48518
1994	94.78092
1995	94.35498
1996	94.40301
1997	95.7988
1998	95.85984
1999	96.24115
2000	97.31004
2001	95.37168
2002	94.87264
2003	91.76342
2004	92.18807
2005	95.35319
2006	99.5434
2007	104.14064
2008	106.43858
2009	105.87074
2010	104.34076
2013	102.98979
2014	103.27688
2015	102.18286