Note: Sega's Numbers before 2000 come from two PDF's of studies done on the Video game industry (see Sources)
Here's a better source with more accurate numbers, Sega's 1998 Annual report has a six year financial summary with data back to 1993:
SEGA Enterprises, Ltd. Annual Report 1998
SEGA Enterprises, Ltd. Annual Report 1999
SEGA Enterprises, Ltd. Annual Report 2000
SEGA Enterprises, Ltd. Annual Report 2001
SEGA Enterprises, Ltd. Annual Report 2002
SEGA Enterprises, Ltd. Annual Report 2003
SEGA Enterprises, Ltd. Annual Report 2004
SEGA-SAMMY HOLDINGS Archived Reports