I thought this might be of general interest. I leveraged pyright's ability to generate type coverage scores of the most downloaded PyPI packages (I used August top 1000). A few are missing, because they either failed to pip install on my MacBook or they are native code. I also looked for type stubs, looking first in typeshed, then for a '<package>-stubs' package, then 'types-<package>', and included the version number of that package, if found.
Overall, here was the distribution of scores for packages with py.typed:
And without:
Thanks
Graham