Year	Percent
1999	18.70859
2000	18.43567
2001	20.87193
2002	21.71907
2003	21.18367
2004	22.31676
2005	22.20193
2006	22.21063
2007	20.81227
2008	20.82704
2009	21.30181
2010	20.03578
2011	20.25516
2012	19.55423
2013	18.3579