Year	Percent
1990	35.85738
1991	25.87935
1992	53.35242
1993	54.69418
1994	48.40959
1995	42.7681
1996	38.517
1997	50.84983
1998	56.08546
1999	52.15374
2000	47.21331
2001	42.2793
2002	45.23264
2003	43.41295
2004	50.16596
2005	51.0334
2006	54.76018
2007	61.97635
2008	68.34559
2009	54.37145
2010	58.09132
2011	66.0677
2012	66.84058
2013	61.46076
2014	64.87507
2015	65.04353
2016	64.71035
2017	68.84741