Hi Emily,
Sorry for the slow turnaround for your question. Your post was marked as spam. Our web guru explains: “There was some errant HTML in the microdata portal post which I removed. It probably came from copying and pasting some text. That probably triggered the spam filter.”
The reason you aren’t getting data for those two attributes is, almost certainly, that they are not available for the year 1940. When I try 2017, data for those attributes comes in.
I think the attribute descriptions should include the years for which data is available.
I hope that helps,
Bill