Year	Percent
1970	63.54953
1972	79.882
1974	73.10378
1975	70.93029
1976	42.35893
1977	57.99822
1978	64.05981
1979	69.54271
1980	75.47496
1981	80.13389
1982	87.25371
1983	82.94925
1984	81.62999
1985	83.74793
1986	83.87206
1987	88.73265
1989	94.49024
1990	96.759
1991	99.2435
1992	99.16515
1998	97.30782
2001	107.26385
2002	112.58954
2003	105.18564
2005	101.19216
2006	100.22676
2007	97.52647
2008	92.57912
2009	92.49631
2010	99.09523
2011	100.40672
2012	97.56892
2013	98.50863
2014	98.01249
2015	98.71413
2016	100.64055