Year	Percent
1986	51.02463
1987	49.57047
1988	46.80627
1989	48.68362
1990	52.27599
1991	47.16921
1992	38.27529
1993	39.37405
1994	36.11058
1995	41.16431
1996	35.06463
1997	34.48137
1998	34.26561
1999	34.42727
2000	42.66598
2001	47.00995
2002	46.64981
2003	36.24027
2004	41.57351
2005	56.95094
2006	45.45477
2007	41.47535
2008	38.63272
2009	32.49285
2010	41.13108
2011	54.34254
2012	55.7185
2013	45.44965
2014	50.31986
2015	44.85205
2016	73.77667
2017	78.48688