Year	Percent
1998	17.96366
1999	18.61814
2000	20.04444
2001	19.34743
2002	20.45283
2003	26.08295
2004	23.05623
2005	22.6056
2006	22.7505
2007	22.86989
2008	22.40992
2009	22.1381
2010	21.2401
2011	20.45278
2012	19.56664
2013	16.10993
2014	22.78511