Year	Percent
1971	56.95032
1972	53.96438
1973	60.03992
1974	60.76884
1975	66.47594
1976	65.06253
1977	67.48576
1978	70.93395
1979	59.51924
1980	61.47049
1981	81.66984
1982	62.95188
1983	63.52466
1984	67.15526
1985	67.7253
1986	70.77039
1987	72.11069
1988	71.78642
1989	76.48453
1990	81.25221
1991	75.11378
1992	69.64487
1993	73.97659
1994	80.3984
1995	90.13957
1996	87.2258
1997	89.44354
1999	87.71288
2000	86.83071
2001	88.0777
2002	93.43059
2003	97.24532
2004	100.7036
2005	103.51286
2007	102.84239
2008	92.37203
2009	88.80508
2010	99.05167
2013	96.81571
2014	99.64298
2015	103.15429