"Area of concerns" vs "Areas of concern"

I would say "areas of concern" (that is, areas or issues that you are concerned about).

Thanks, Doctor D. That is what I thought. But I've got a lot more hits in Google on "Area of concerns" than I expected. Some people even start with "areas of concern", and then when focusing on one particular area afterwards, they change to "area of concerns", which I guess means that there are multiple concerns in that one particular area. This is weird to me, but I hesitate to say that they are

The Ngram server reports that "area of concerns" is almost nonexistent. When it appears (and this seems true of your google search results as well), it means one area with multiple concerns. The much more common term "areas of concern" means multiple areas we ought to worry about.

Thank you for the tips on using Ngram!