This is a good chart, thanks Ray. I wish we could find one like it for design patents, too. It's great to have patent information in the new PDF pages. I wish that on the US patent site that one could look up patents by date. I think that is not possible until around 1957 or so onwards. That would make it a lot more convenient that going through the old patent records -- though I know I'll enjoy doing that when I get to a patent office.
Charles