Year	Percent
1970	2.39279
1971	1.89219
1972	2.03893
1973	2.52494
1974	2.95776
1977	5.29368
1978	4.76079
1979	3.54853
1980	3.31399
1981	4.12701
1982	5.9543
1983	6.83051
1984	6.75486
1985	6.43411
1986	7.23621
1987	5.97626
1988	8.23662
1989	8.53983
1990	48.51727
1991	117.34982
1992	31.78602
1993	12.44022
1994	13.25924
1995	13.58158
1996	10.29265
1997	8.08648
1998	8.79656
1999	7.59022
2000	7.15049
2001	7.69782
2002	7.39862
2003	6.53948
2004	5.80446
2005	4.34341
2006	3.54265
2007	3.59033
2008	3.00607
2009	3.97181
2010	3.75615
2011	3.5014
2012	3.41374
2013	3.27153
2014	3.58566
2015	5.03073
2016	5.841
2017	5.75117