Year	Percent
1998	22.67559
1999	21.13764
2000	21.90981
2001	21.9474
2002	23.7001
2003	25.07658
2004	23.86169
2005	23.52279
2006	24.51716
2007	25.60264
2008	24.69042
2009	28.56748
2010	31.34917
2011	29.59549
2013	22.11209
2014	22.90335
2015	23.42331