I think you have to look at things not just when they were made, but also when they were made available to the Rebellion. T-65's might be older, but weren't used by Rebels until Lothal or so.

You will probably have to break it up into phases. A-wings and Z-95's probably used first. Then Y-wings and B-wings added. Next comes X-wings. I wouldnt say there were K-wings or E-wings before Endor. The same for Empire and when things entered production.