Year	Percent
1999	21.49918
2000	21.5881
2001	20.96853
2002	24.46539
2003	23.49934
2004	23.66789
2005	25.01545
2006	25.50708
2007	25.07161
2008	25.53272
2009	25.52614
2010	25.08811
2011	25.70315
2012	24.34177
2013	24.29029