Year	Percent
1991	29.53255
1992	27.76957
1993	30.30694
1994	30.99572
1995	39.11579
1996	41.34083
1997	46.87738
1998	54.36175
1999	58.2079
2000	70.31291
2001	65.96305
2002	59.97945
2003	60.17772
2004	63.44776
2005	64.80425
2006	75.07055
2007	77.25611
2008	78.9185
2009	70.37099
2010	76.52326
2011	80.64301
2012	79.72044
2013	78.68423
2014	81.26945
2015	81.35329
2016	79.45581
2017	82.27033