Year	Percent
1970	18.08922
1971	22.12563
1972	22.55655
1973	22.28732
1974	22.08514
1975	24.38982
1976	25.21567
1977	37.55303
1978	42.24369
1979	42.85779
1980	47.3133
1981	48.89736
1982	55.48558
1983	60.84037
1984	66.87768
1985	80.40215
1986	77.28906
1987	95.81707
1988	99.1376
1989	181.70986
1990	211.22829
1991	243.61615
1992	160.51742
1993	144.08504
1994	127.52285
1995	118.78589
1996	111.35274
1997	103.9241
1998	97.25509
1999	101.39475
2000	129.22367
2001	130.07868
2002	134.85914
2003	122.5146
2004	112.06371
2005	100.44755
2006	90.67012
2007	84.76109
2008	62.40797
2009	59.62651
2010	65.13931
2011	61.83095
2012	60.50673
2013	69.6834
2014	68.57193
2015	69.35328
2016	70.73158