I have met only three others. And none of then were even close to my age. I was the only Charlotte in my entire high school and now college.
Perhaps it is a name that is becoming old, like edna, or ethel, or agnus (after all my sis was named after two of our great-grandmothers), or maybe it just depends where you live, like in NZ there's hardly anyone here with my name, but I went to california, and I found a novelty keyring with my name on it!