Year	Percent
1971	155.31376
1972	195.53351
1973	157.79456
1974	274.13246
1975	318.09198
1976	137.87897
1977	66.85839
1978	28.02103
1979	15.81631
1980	26.84844
1981	9.90694
1982	10.02403
1983	6.29434
1984	6.89452
1985	7.31105
1986	23.76537
1987	46.05933
1988	56.21352
1989	66.71991
1990	81.64753
1991	92.25386
1992	89.06847
1993	86.67906
1994	70.20106
1995	62.69461
1996	65.68721
1997	53.09653
1998	45.01865
1999	57.92412
2000	94.5801
2001	98.3132
2002	134.08829
2003	159.77105
2004	172.14442
2005	170.37904
2006	195.30094
2007	256.41572
2008	267.76876
2009	102.23171
2010	95.78252
2011	29.11334
2012	30.1942
2013	26.21355
2014	25.79169
2015	29.09116
2016	27.64065