Year	Percent
1984	53.46674
1986	46.13542
1987	50.76694
1988	50.21421
1989	50.15206
1990	50.54593
1994	53.11776
2000	70.11994
2001	68.01724
2002	65.92249
2004	67.09818
2005	67.70705
2006	68.78136
2007	68.94382
2008	69.42785
2009	69.91694
2010	70.63737
2011	72.2136
2012	72.37915
2013	71.72842
2014	71.88325
2015	71.40463
2016	70.59669
2017	69.77762