Year	Percent
1997	59.04236
1998	77.34779
1999	69.68476
2000	82.00256
2001	68.99608
2002	46.84616
2003	51.78216
2004	58.84625
2005	53.90302
2006	70.34884
2007	53.31453
2008	17.99502
2009	25.9366
2010	27.19889
2011	45.34927
2012	48.31683
2013	71.06527
2014	55.58558
2015	44.04727
2016	39.31139
2017	43.91388