Year	Percent
1991	24.36798
1992	22.12022
1993	13.83732
1994	10.20057
1995	26.08958
1996	28.13043
1997	24.52876
1998	26.00441
1999	27.69804
2000	27.33694
2001	25.85531
2002	25.067
2003	30.69357
2004	27.34299
2005	27.4181
2006	29.35101
2007	30.48112
2008	28.84433
2009	27.49253
2010	25.40719
2011	27.85633
2012	35.56474
2013	36.70009
2014	38.1649
2015	41.08382
2016	38.70231
2017	43.35583