SegaSammy revealed its sales figures for some of its series with Sonic the Hedgehog selling more than 1.66 Billion units and downloads clearly leading the way for the company. The other series that trail Sonic is Like A Dragon and Persona which is very far back of the popular hedgehog.
According to the SegaSammy document, The Persona series has sold approximately 17.7 million units and downloads over the years.
What might’ve and likely held the series back in sales was the limitation of platforms it had in the early days. ATLUS and Sega would release Persona games exclusively for PlayStation most of the time with Nintendo receiving an exclusive rarely. Now that Persona 5 Royal, Persona 5 Tactica, and Persona 4 Golden are available on multiple platforms the sale numbers should go up.