Year	Percent
1961	31.30253
1962	78.83076
1963	69.76639
1964	93.83468
1965	51.38487
1966	39.40589
1967	29.24484
1968	26.67068
1969	20.91402
1970	17.09228
1971	20.25389
1972	19.14441
1973	22.66485
1974	34.80019
1975	33.86228
1976	47.62699
1977	46.17957
1978	41.0598
1979	56.48057
1980	87.30688
1981	107.21403
1982	104.83236
1983	140.19563
1984	212.78578
1985	231.7235
1986	145.27154
1987	204.10342
1988	651.11386
1989	1209.12133
1990	2700.44214
1991	414.23626
1992	968.18426
1993	2001.34773
1994	2302.84078
1995	89.49744
1996	18.45778
1997	7.72883
1998	4.92409
1999	8.00929
2000	5.88548
2001	8.23264
2002	9.79752
2003	14.09208
2004	7.74753
2005	7.43713
2006	6.77909
2007	6.44859
2008	8.78201
2009	7.31344
2010	8.40965
2011	8.30729
2012	7.93049
2013	7.49884
2014	7.84214
2015	7.57064
2016	8.14439
2017	3.79122