Year	Percent
1990	14.08232
1991	14.60524
1992	15.4418
1993	15.61049
1994	16.02575
1995	16.29197
1996	16.93864
1997	16.98429
1998	14.10832
1999	13.3064
2000	12.84626
2001	12.69319
2002	12.09117
2003	12.10175
2004	11.81599
2005	12.42728
2006	13.71187
2007	13.53489
2008	13.58939
2009	12.22991
2010	12.14699
2011	12.38154
2012	12.88795
2013	13.30951
2014	13.60544
2015	13.6276
2016	13.67678