Year	Percent
1975	68.49228
1976	70.37808
1977	75.99624
1978	76.23579
1979	80.31738
1980	83.09709
1981	84.40605
1982	84.28368
1983	85.04619
1984	88.02501
1985	86.35081
1986	88.00828
1987	88.75115
1988	88.58224
1989	88.36041
1990	86.61977
1991	86.3184
1992	87.64145
1993	88.58051
1994	90.2368
1995	93.20427
1996	94.89245
1997	94.91249
1999	94.93766
2000	95.46411
2001	95.94746
2002	97.18852
2003	96.93486
2004	98.45136
2005	98.83715
2006	98.57848
2007	98.48267
2008	96.85586
2009	94.41425
2010	94.01768
2011	94.07039
2012	100.41058
2013	104.45168
2014	106.36774
2015	101.78917
2016	101.33267