Year	Percent
1998	9.87979
1999	10.43176
2000	10.6055
2001	13.3067
2002	12.09947
2003	12.6783
2004	12.65445
2005	14.51082
2006	15.67011
2007	16.7449
2008	17.06021
2009	14.97703
2010	15.81208
2011	15.34403
2012	16.18243
2013	17.06526
2014	16.71444
2015	16.94954
2016	17.55741