Year	Percent
1970	0
1971	0
1972	0
1973	0
1974	0
1975	7.0928
1976	15.40149
1977	23.67498
1978	44.29644
1979	59.49267
1980	131.0928
1981	97.62656
1982	104.3125
1983	121.84895
1984	183.53138
1985	200.20968
1986	288.20942
1987	291.41511
1988	366.53763
1989	296.50068
1990	297.66077
1991	311.28431
1992	357.8866
1993	355.08669
1994	383.48885
1995	378.84314
1996	371.61266
1997	362.845
1998	504.47681
1999	447.48754
2000	265.20575
2001	239.94087
2002	240.21979
2003	228.93808
2004	214.04227
2005	177.74544
2006	178.6578
2007	157.82581
2008	129.24352
2009	141.00434
2010	131.17226
2011	25.67589
2012	28.09382
2013	27.04294
2014	24.56262
2015	29.90215
2016	26.2681