As of May 1998, approximately 5,425 veterans (0.78%) out of 697,000 participants in the 1990-1991 Gulf War had died. The Defense Manpower Data Center (DMDC) obtained this number by comparing lists of all 1990-1991 Gulf War veterans with files of deaths recorded by the Social Security Administration. A similar comparison disclosed that, of the 2,372,327 members of the active duty force and the selective reserve who did not deploy to the Gulf, 19,475 (0.82%) had died. No information on cause of death was available from this data search. Previous studies by the Department of Veterans Affairs had compared deaths among GW veterans to those among a random sample (about half) of all other veterans. The overall death rates were about the same in the two comparison groups. GW veterans had higher rates of death due to external causes, particularly due to motor vehicle accidents. GW veterans had lower rates of death from natural causes.