What percentage of microservice architectures employ polyglot programming models? One of the tenets of microservices is the polyglot, autonomous services (developed in different programming languages). In my experience (online reading and YouTube and discussions with developers) it seems this is not really applied in practice except the big companies like NetFlix, AWS , Google. Will this assumption be true ? I  will appreciate information on statistics about this e.g. reports, surveys.
A good source for statistics could be stackshare.io.

In general, polyglot services i.e. teams delivering different stacks could create silos, and additional overhead for diverse toolchains; nevertheless I consider that larger organizations have the polyglot situation organically because this type of thing is not always an issue of top-management. 

Arguments against polyglot approach:
"Why You Should Think Twice Before Even Considering Polyglot Microservices"

Worth to mention is the polyglot toolkit Eclipse vert.x (though I am not sure how is this different to say "it has bindings to many languages").