Year	Percent
1988	7.07412
1989	7.30145
1990	8.06953
1991	9.77794
1992	10.43485
1993	11.4808
1994	14.08046
1995	12.85512
1996	12.07011
1997	11.72968
1998	11.4615
1999	11.09083
2000	15.35994
2001	15.48856
2002	16.51967
2003	13.69852
2004	13.5333
2005	12.76763
2006	12.31833
2007	10.25721
2008	10.78837
2009	11.92576
2010	11.86682
2011	13.0671
2012	12.72959
2013	12.90999
2014	13.59873
2015	13.51306
2016	14.78156