I have been searching all over for CPS microdata for the Unemployment Insurance Non-Filer (UINF) Supplements for the years 1976, 1989, 1993, and 2005. I noticed that IPUMS CPS does not have the supplement available for any of these years. I have been able to find the 2018 microdata for the CPS UINF on census’ website. But I noticed that the data were no where to be found on NBER’s website either. I was wondering why this is the case? Are these data restricted in some unique way?
Any guidance/ information would be great!