Year	Percent
1970	63.81936
1973	64.77767
1974	67.90094
1975	69.20544
1976	75.13364
1977	81.51117
1978	80.32278
1979	80.34115
1980	79.10524
1981	78.14256
1985	83.24869
1993	87.30782
1995	88.91474
1998	97.70431
1999	102.64685
2000	101.27117
2001	96.8509
2002	96.78271
2003	102.07601
2004	102.33273
2005	102.60042
2006	103.61074
2007	105.87557
2008	104.88213
2009	101.93239
2010	103.35593
2011	99.77337
2012	94.00942
2013	95.14781
2014	95.90407
2015	99.44596
2016	102.78095