Then AS/OC would be around #8 or something, they probably just didn't included sub-units.
Now that i thought about it, imagine the SNSD graphic if they included TTS, omg
This chart does include sub-units. TTS is included with SNSD, OC is included with AfterSchool and even solo singles are included (Soyu's solo collab is included with SISTAR).
Back in 2012 they were accused of bullying a fellow member who left afterwards, and it really hit them hard. They used to be one of the most popular girl groups