Year	Percent
1989	78.1974
1990	78.29268
1991	79.43503
1992	78.0284
1993	76.66574
1994	77.84185
1995	77.33402
1996	78.36155
1997	78.32252
1998	79.42312
1999	78.60796
2000	78.68466
2001	78.51414
2002	78.85481
2011	79.50168
2012	81.15532
2013	79.86859
2014	79.8706
2015	78.96783
2016	77.62944