Year	Percent
1998	19.62106
1999	19.38165
2000	20.18436
2001	20.93246
2002	21.35733
2003	22.17697
2004	22.15535
2005	22.28554
2006	23.01221
2007	24.62767
2008	26.80364
2009	28.60976
2010	27.99309
2011	27.3279
2012	23.5222
2013	22.98916
2014	22.57166