Complex sentence: The SSDI is a popular tool for genealogists and biographers because it contains valuable genealogical data: the deceased person's birth date, death date, SSN, state or territory where the SSN was issued, and last place of residence.
Split into simpler sentences: The SSDI is a popular tool for genealogists and biographers. The database contains valuable genealogical data: the deceased person's birth date, death date, SSN, State or Territory where the SSN was issued, and last place of residence.