Year	Percent
1990	18.60179
1991	17.51096
1992	15.29807
1993	14.73454
1994	14.3567
1995	14.64776
1996	14.61967
1997	15.72142
1998	15.30079
1999	14.98795
2000	15.0024
2001	14.39847
2002	14.1327
2003	15.39154
2004	14.78794
2005	14.64732
2006	16.11171
2007	15.24178
2008	15.77605
2009	15.55576
2010	14.21559
2011	14.46073
2012	13.96587
2013	14.24282
2014	13.87698
2015	13.86626
2016	12.6638