(Edited to provide context and clarify what I'm interested in)
Context: I am reading a paper that involves comparing German, Dutch, and English. German is the outlier for the phenomena and measures discussed in the paper; I believe this is partially explainable by the difference in the degree of synthesis (as approximated by average morphemes/word ratio). As well, I think that repeating the procedures described in this paper on a language more synthetic than German would show a trend. Another paper relevant to the first has some measures related to Russian, so I am curious about Russian in particular - how synthetic is it, relative to any of the other languages involved (especially the two outliers of the three used in the first study)? I am interested in a morphemes/word ratio in particular as a simple cross-linguistic and quantitative point-measurement that also allows for easy relative comparisons.
Accordingly, if there's some general typology survey out there that gives average morpheme/word ratios for a bunch of languages (including enough of the ones I might find useful or generally interesting) - that would suffice. Alternatively, if someone only knows of papers surveying the specific languages I've mentioned - that's fine, too.
Searches for "morpheme per word" (with an optional search term of a specific language) don't seem to yield anything with actual numbers, although I'm certain I've seen numbers for English and German before.