Year	Percent
1972	86.98054
1973	87.88229
1974	91.8318
1975	92.9166
1976	93.05297
1977	94.19758
1978	98.28145
1979	96.68396
1980	97.57938
1981	96.87838
1982	98.78667
1983	101.2368
1984	109.0195
1986	103.00477
1998	70.41291
1999	68.07923
2000	64.35285
2002	64.01457
2004	74.20525
2005	92.51346
2006	86.56638
2007	90.5672
2008	94.22325
2009	87.72395
2010	90.88159
2012	85.75811
2013	79.70395