AESC 1990-2017 download with year = 0 observations

I downloaded some person-level income and tax variables from 1990-2017 AESC. In my final extract, which has about 3 mil observations, ~50% of them have year == 0. For such observations, all other variables are also zero, except the FICA (Social Security retirement payroll deduction) and FILESTAT (tax filer status) variables. I could just drop the year == 0 observations, but that seems fishy. Am I misspecifying the download or missing something important?

I just downloaded your most recent data extract (#7) and everything seems to be working properly. Specifically, I don’t see any observations with YEAR == 0. I wonder if your .dta.gz file is being completely unzipped or decompressed. We typically recommend 7zip for this process.

I used 7zip and it worked without problem, thanks!