Hello everyone

I'm a Game design student and have to give a presentation about (console) MMOs, using PSO as an example. I want to give a proper introduction about it and would like to mention the total sales numbers, however, can't seem to find anything (found the first week sales on this page in comparison to the new Phantasy Star Portable, but that's about it)

Does anyone know the numbers or a source? Preferably for all PSO releases but at the very least the original Dreamcast release