Year	Percent
1990	70.60573
1991	70.98516
1992	71.74381
1993	71.19913
1994	71.93834
1995	70.71766
1996	71.37085
1997	70.51332
1998	69.03345
1999	69.17896
2000	69.84783
2001	70.07524
2002	72.2252
2003	70.31009
2004	71.40581
2005	70.49881
2006	71.00975
2007	74.39072
2008	75.22302
2009	74.66425
2010	74.48366
2011	71.96786
2012	72.48596
2013	73.18157
2014	72.74404
2015	74.09007
2016	74.8954