Year	Percent
1970	12.18303
1971	12.35252
1972	12.0503
1973	10.39752
1974	9.69547
1975	8.88125
1976	9.99413
1977	10.28
1978	17.68804
1979	27.64427
1980	55.81146
1981	53.37603
1982	40.64736
1983	45.97775
1984	30.10233
1985	35.72778
1986	36.68014
1987	31.10644
1988	30.08031
1989	42.14903
1990	61.64131
1991	85.8975
1992	106.52925
1993	96.25734
1994	86.46667
1995	63.33679
1996	61.84984
1997	62.49717
1998	59.94081
1999	59.1177
2000	58.09043
2001	66.5789
2002	66.50292
2003	73.78127
2004	62.00305
2005	50.995
2006	13.41679
2007	13.7107
2008	16.40031
2009	13.22239
2010	14.9914
2011	16.17
2012	16.39967
2013	35.8876
2014	32.7733
2015	36.20759
2016	39.63123