Year	Percent
1990	44.88861
1991	51.88263
1992	55.74472
1993	52.23626
1994	60.12046
1996	58.88929
1997	55.99395
1998	60.41667
1999	61.72018
2000	71.59838
2001	61.68691
2002	58.9825
2003	60.00713
2004	58.13226
2005	51.99911
2006	58.11828
2007	52.43745
2008	50.23138
2009	47.98409
2010	47.08011
2011	47.23403
2012	45.73184
2013	38.5529
2014	34.41303
2015	30.19682
2016	21.47378