[amelia] amelia help

I have a question about the appropriateness of using Amelia to impute some data for items that were not asked in earlier years of a survey. I'm working with a governmental survey collection that started in 1975 and continues up to the present day. The data are in long form arranged by state and year. My question is that certain items were not asked in the earlier years that are asked now. Is appropriate to impute the data for these earlier years? Initially, I planned to develop multiple datasets to maximize years and states, but I started thinking this may be an imputation issue as well. Best regards, Matthew