SEGA Sammy has released their Japanese Annual Integrated Report 2021 which gives numbers for a number of franchises including the Persona series along with its respective merchandise and the Megami Tensei series and its respective merchandise. These can include things such as pachislot and pachinko machines, amusement machines, and toys.
The latest report from SEGA Sammy says that the Megami Tensei series has now shifted over 17.7 million games along with merchandise over the past 35 years. These published figures also include the free-to-play mobile game Shin Megami Tensei: Liberation Dx2. The report also states that the beloved Persona series has now sold 15 million games and merchandise over the past 25 years.