Year	Percent
1998	28.44399
1999	27.92332
2000	29.6705
2001	27.12187
2002	25.09889
2003	22.80021
2004	22.19263
2005	22.96793
2006	24.69993
2007	25.40809
2008	31.73957
2009	36.05238
2010	31.37269
2011	29.37498
2012	29.29423
2013	25.23844
2014	22.19076