Year	Percent
1970	47.7234
1971	42.11495
1972	43.75415
1973	48.28818
1974	43.03717
1975	43.39956
1976	47.54791
1977	58.98413
1978	65.23152
1979	67.6157
1980	72.95686
1981	71.14194
1982	77.9128
1983	77.44812
1984	76.3679
1985	94.65528
1986	103.05547
1987	121.36736
1988	102.48589
1989	91.54556
1990	84.80379
1991	77.18725
1992	97.06764
1993	90.01282
1994	177.50425
1995	165.8277
1996	103.10623
1997	84.87957
1998	142.69713
1999	158.98325
2000	159.10333
2001	153.96003
2002	84.05107
2003	98.22751
2004	100.38963
2005	88.38283
2006	21.98439
2007	19.69486
2008	18.77161
2009	18.66077
2010	14.89715
2011	15.38362
2012	22.55405
2013	29.12683
2014	28.13354
2015	27.94468
2016	34.69913