As of 2019-06-11 10:00 AM GMT, there was 49,464 binary RPM packages by name and module stream in Fedora 30. Of those, 1,119 (2.26%) came from a module stream.
First, you need the modular-repoquery script from asamalik/modular-repoquery.
Then you can list all packages in fedora by running the following command. The script is not very optimized, this took about 50 minutes for me.
./modular-repoquery > all-pkgs.txt
Finally, get the numbers:
./count-packages.sh