Date of death from administrative data. This variable is obtained using a hierarchy of administrative sources: (i) SSA's MBR file, (ii) SSA's SSR file, and (iii) the Census PCF with death information coming from the SSA Numident and Master Death Files. This variable is coded as a SAS date variable. This format gives the number of days between the date of death and January 1, 1960. An individual who died on January 1, 1959 would have deathdate=-365 and an individual who died on January 1, 1961 would have deathdate=365.