Year	Percent
1989	32.1403
1990	28.72016
1991	23.9447
1992	21.98997
1993	26.19088
1994	38.55515
1995	50.15645
1996	48.20471
1997	43.65019
1998	44.16188
1999	48.24792
2000	57.41342
2001	53.83417
2002	50.70679
2003	55.18171
2004	53.69777
2005	50.64084
2006	49.47138
2007	50.36262
2008	54.9111
2009	48.04975
2010	51.08668
2011	56.42547
2012	56.37228
2013	52.19295
2014	52.09882
2015	54.48398
2016	55.51934
2017	54.26726