Year	Percent
1985	30.65815
1986	31.95856
1987	34.85929
1988	35.9945
1989	36.78675
1993	35.35999
1994	31.96715
1995	27.63522
1996	26.93784
1997	26.96494
1998	26.43614
1999	27.2181
2000	26.08089
2005	27.30001
2006	24.69255
2007	23.25126
2008	22.36789
2009	25.2417
2010	27.85139
2011	31.49107
2012	30.40518
2013	28.06606
2014	30.08247
2015	29.59858
2016	31.67351