Year	Percent
1970	19.38784
1971	18.89103
1972	20.15754
1973	13.98776
1974	10.72998
1975	14.86708
1976	18.56329
1977	20.72399
1978	23.40347
1979	30.85825
1980	35.81556
1981	46.60135
1982	55.25604
1983	47.01469
1984	65.41719
1985	61.13924
1986	49.7423
1987	55.42862
1988	48.88772
1989	93.33371
1990	46.22833
1991	35.71921
1992	30.55514
1993	27.68068
1994	29.59448
1995	38.98486
1996	41.68248
1997	44.74284
1998	48.53657
1999	55.02947
2000	54.2417
2001	58.49329
2002	163.58177
2003	136.48308
2004	108.21945
2005	68.39935
2006	52.87276
2007	43.14384
2008	36.79793
2009	41.42598
2010	30.95243
2011	27.08114
2012	25.61087
2013	27.13001
2014	28.21503
2015	30.2435
2016	35.71719