Year	% of expense
1999	23.89767725163931
2000	24.089937449483664
2001	28.243116918404983
2002	30.67864884796746
2003	34.778099711093006
2004	35.34490982337319
2005	29.913021710563083
2006	29.69223725606084
2007	38.9250640168288
2008	36.82065052866593
2009	34.31710428602069