Indicates a Company that performs Gilbert & Sullivan almost exclusively, though they may do non-G&S concerts.
Indicates a Company that performs Gilbert & Sullivan regularly (at least every two or three years).
Indicates a Company that has performed Gilbert & Sullivan within the past ten years.
Indicates a Company that doesn't list its performance history, but that seems a likely candidate to perform G&S in the future.
Indicates a Company that has performed Gilbert & Sullivan in this century.