Following this question on SE Academia: Easy way to see historical trend in keywords in publications?, I'm using Google Scholar and the linked script (https://github.com/Pold87/academic-keyword-occurrence) to get the number of publications on a certain keyword.
For the record, I was using the tool to get some statistical data for the popularity of the keyword "inter(-)organis(z)ational trust" (multiple spellings) (this should not matter for the the actual question though).
I found that there are very few to no publications at all on this topic between the 1940s and 1985. I'm wondering if this is (was) actually the case OR if this is just because there's no data on Google Scholar that dates back to that era, i.e. there were indeed publications on that topic but none of them got into Google Scholar because no-one cares about those publications now.
So my question is whether you think the part of publications before 1985 that is not on Google Scholar is really "negligible" and the numbers on Google Scholar are representative (historically accurate) for the period of time between 1940 and today.
FYI, I attached a plot of the numbers from GS:
If not GS, do you think the data on Constellate (https://constellate.org) is attendible (or is there literally any service you know of that fits this purpose)?