Year	Percent
1998	30.8487
1999	29.24041
2000	27.51983
2001	27.07266
2002	23.70152
2003	26.05286
2004	22.13264
2005	21.21997
2006	21.59054
2007	21.24627
2008	19.92001
2009	20.78114
2010	19.79175
2011	19.16092
2012	19.23424
2013	20.07999
2014	19.08355