For industry and occupation in the non-ASEC samples, there are versions using both the 1950 and 1990 base, e.g. IND50 and IND90. The 1990 version does not appear to be available for the ASEC variables, for which respondents reported the industry/occupation in which they worked in the last year (INDLY and OCCLY). There are 1950 versions of these, which I can use, though I would have a preference for the 1990 versions if possible. Will these be created at some point in the future?