Year	Percent
1986	33.05509
1987	31.08014
1988	29.7406
1989	34.99448
1990	38.58896
1991	35.71643
1992	38.79781
1993	41.22973
1994	43.70372
1995	44.06139
1996	42.51129
1997	42.15316
1998	41.72795
1999	40.07081
2000	38.73464
2001	38.62953
2002	38.48388
2003	37.98756
2004	37.98355
2005	42.56888
2006	42.68848
2007	42.83328
2008	42.50916
2009	43.44335
2010	36.94247
2011	36.73274
2012	37.26681
2013	38.7362
2014	39.03639
2015	39.73329
2016	40.92468