Year	Percent
1970	62.79813
1983	83.43171
1985	83.17864
1986	84.11028
1987	88.45801
1989	94.02864
1990	97.04659
1991	99.25946
1992	99.19924
1998	97.15291
2001	106.55314
2002	111.09134
2003	104.88375
2005	101.01083
2006	100.33148
2007	97.1794
2008	92.53695
2009	92.12038
2010	98.04446
2011	98.28581
2012	96.902
2013	97.1329
2014	96.92144
2015	97.67877
2016	99.54609