Year	Percent
1985	72.83792
1986	57.14509
1987	61.36865
1988	45.09497
1989	38.85218
1990	40.21299
1991	38.14959
1992	38.13398
1993	40.58277
1994	39.40171
1995	40.85952
1996	39.25357
1997	35.63665
1998	37.81721
1999	39.27571
2000	34.15929
2001	27.5521
2002	30.86175
2003	29.06
2004	29.0739
2005	33.27549
2006	38.6126
2007	52.67239
2008	62.76801
2009	73.04717
2010	45.55344
2011	40.92228
2012	39.56321
2013	36.97653
2014	38.70868
2015	31.07876
2016	35.46359