Year	Percent
1974	0.72099
1975	0.77954
1976	2.83434
1978	7.73372
1979	12.22898
1983	23.3769
1984	29.45966
1985	29.97116
1986	35.98651
1987	39.15192
1988	46.80628
1989	54.55125
1990	62.13865
1992	69.71395
1994	70.8807
1995	73.60704
1996	77.12061
1997	80.77178
1998	82.3512
1999	84.32302
2000	82.03125
2001	84.68989
2002	85.8517
2003	87.5532
2009	93.8178
2011	98.68199
2012	100.87338
2013	97.73544
2014	105.47459
2015	100.82658
2016	104.04313