Year	Percent
1990	25.03167
1991	43.70764
1992	66.47422
1993	55.13739
1994	58.15444
1995	56.68491
1996	52.28678
1997	55.06735
1998	46.65717
1999	47.47853
2000	54.06572
2001	57.79478
2002	57.48239
2003	62.19285
2004	68.71248
2005	72.04563
2006	81.02664
2007	83.27576
2008	80.04534
2009	67.60925
2010	76.33526
2011	85.04703
2012	91.43012
2013	93.8195
2014	91.85296
2015	92.96751
2016	94.62461
2017	96.3035