Year	Percent
1990	33.31001
1991	46.20093
1992	69.72931
1993	59.66271
1994	52.97772
1995	54.55338
1996	62.9365
1997	64.4735
1998	57.26502
1999	51.87796
2000	56.63371
2001	65.82086
2002	64.71374
2003	64.09015
2004	71.44935
2005	76.63377
2006	85.00446
2007	84.39509
2008	82.87559
2009	69.09228
2010	77.7878
2011	85.96084
2012	87.76375
2013	89.58596
2014	88.42586
2015	91.36024
2016	91.1225
2017	92.87703