Year	Percent
1990	39.67624
1991	33.83142
1992	30.58904
1993	28.24475
1994	27.03522
1995	29.17603
1996	28.65353
1997	26.78635
1998	19.36902
1999	20.22054
2000	31.558
2001	26.5407
2002	44.7678
2003	57.31707
2004	63.75596
2005	63.71684
2006	73.55966
2007	72.69901
2008	72.50739
2009	59.23601
2010	65.60497
2011	54.82945
2012	74.62246
2013	70.43373
2014	47.01433
2015	38.01073