Year	%
1970	70.71429
1971	80.68548
1972	81.65565
1973	76.83119
1974	76.98541
1975	75.61108
1976	77.51803
1977	78.35956
1978	81.99453
1979	83.08805
1980	83.50715
1981	81.98354
1982	81.83344
1983	81.85251
1984	79.57245
1985	79.72484
1986	80.57679
1987	81.51113
1988	88.66213
1989	86.14725
1990	87.26542
1991	99.88072
1992	93.47826
1993	89.93511
1994	87.38385
1997	87.41307
1998	91.01249
1999	84.24658
2000	88.86433
2001	84.14933
2002	84.28097
2003	97.55335
2004	95.09438
2005	97.77688
2009	96.8583
2010	96.84043
2011	96.77192
2012	99.76623
2013	96.81329
2014	100
2015	99.77754
2016	98.1119