Year	Percent
1990	43.86085
1991	45.65868
1992	86.20361
1993	57.43242
1994	24.7226
1995	27.90087
1996	29.5157
1997	29.02188
1998	22.70232
1999	27.98358
2000	39.04136
2001	40.92304
2002	42.76852
2003	42.01088
2004	48.78748
2005	62.93643
2006	66.50634
2007	68.13094
2008	65.77614
2009	51.63575
2010	54.30472
2011	56.42698
2012	52.97468
2013	48.32715
2014	43.26085
2015	37.79478
2016	46.42765
2017	48.68817