Year % of expense 1974 5.435299714557548 1975 5.700735578784357 1976 5.485588707632492 1977 5.77942735949099 1978 5.182197306351266 1979 5.360799156170502 1980 5.211339331183164 1981 5.453217137191461 1982 5.2840284745114925 1983 5.586617573526076 1984 5.6390646976090215 1985 5.839007153322394 1986 5.759293215535909 1987 6.06316976875354 1988 6.057917238041466 1989 6.543200126362329 1990 6.240498631802997 1991 5.714081639941419 1992 5.868791320562824 1993 5.847857423666623 1994 6.109253065774807 1995 5.077619342755029 1996 5.8297372574661726 1997 5.594897419195304 1998 6.0271563836108974 1999 6.008350636220601 2000 6.353522603510953 2001 6.677251396931593 2002 6.693259256821188 2003 6.3349389615280955 2004 6.02804494487626 2005 6.279688535122609 2006 6.063833688154845 2007 6.517884339094541 2008 5.994569697267847 2009 5.976846345936289 2010 6.24290359800494 2011 6.092123398732334 2012 6.123901762738268 2013 6.230083930430571 2014 6.462532618846459 2015 5.949502814732214 2016 5.404011828781245 2017 5.556866903673345 2018 5.824084188638561 2019 5.996748402375703 2020 5.572433356406154 2021 5.71413158771646 2022 6.3319406702401935