Year	Percent
1989	10.09727
1990	8.42932
1991	8.68014
1992	11.24383
1993	11.59887
1994	13.93698
1995	15.17258
1996	15.80527
1997	17.55396
1998	19.25282
1999	20.74644
2000	22.45135
2001	22.056
2002	21.42671
2003	21.3991
2004	21.2854
2005	19.63566
2006	18.98141
2007	17.17706
2008	15.72923
2009	18.17619
2010	16.93781
2011	16.50982
2012	16.33507
2013	15.92476
2014	15.9922
2015	14.68694
2016	15.2892