Social Security Death Index

The Social Security Death Index lists over 72 million names dating from as early as the 1930s compiled from the Social Security Administrations Master Death File.I have yet to find 'Tupac Amaru Shakur' in this. I have even gone back and used his real name " Lesane Parish Crooks" born on June 16th, 1971 and still nothing comes up to match these names? If Tupac is really dead why isn't his name listed in this data base?