Year	Percent
1989	78.94257
1990	80.72502
1991	80.45705
1992	79.77695
1993	78.63501
1994	79.25072
1995	79.90431
1996	80.95855
1997	79.72292
1998	82.07266
1999	80.99885
2000	81.36062
2001	81.55873
2002	83.13378
2011	85.40672
2012	86.63355
2013	85.52403
2014	85.35356
2015	85.54131
2016	84.82829