Year	Percent
1999	21.13236
2000	20.14543
2001	21.84557
2002	22.44984
2003	21.73179
2004	20.90618
2005	20.74393
2006	20.58695
2007	19.78606
2008	19.93193
2009	19.96889
2010	21.55448
2011	22.41433
2012	20.67306
2013	20.86017
2014	20.84701