Year % of revenue 1986 5.023687327279905 1987 8.719299736551372 1988 6.896072297532152 1989 7.161271841879118 1990 6.405803473290833 1991 6.528180456877052 1992 8.267511951777177 1993 8.660115006634998 1994 11.45371969071391 1995 12.546119099341402 1996 9.944011038581966 1997 8.992240198813208 1998 8.636930476996392 1999 6.536274448540899 2000 8.726884291608275 2001 10.544112009620928 2002 10.65806403002899 2003 11.090004078896962 2004 10.430508354990064 2005 9.997973261328312 2006 7.866398390916574 2007 7.994761679699036