Given each toon is a captain of his/her own ship (except FEDs before playing the tutorial, or before skipping it), that 2 million number would logically designate characters.
Why would they show the smaller number of accounts when they can show the much more pleasing amount of toons?
Also an average of 4 ships per toon seems more likely than 4 per account (only getting the free ships at leveling, each one Vice Admiral toon will get to 5).
TOIVA, Toi Vaxx, Toia Vix, T'vritha, To Vrax: Bring in the Allegiance class Toi'Va, Ti'vath, Toivia, Tia Vex, Toi'Virth: Add Tier 6 KDF Carrier and Raider. Tae'Va, T'Vaya, To'Var, T'Vira, To'Vrak: Give us Asylums for Romulans
You have to take charts like this with a grain of salt, if they aren't releasing these numbers or actual empirical data that produces them then it's all conjecture and quite 'cryptic', just like everything DStahl says. If it was really 2 million active accounts it would say 'active accounts' since that's really the only criteria that matters there....inactive accounts are not generating any income potential. Some players have 6-10 toons, number of 'Captain's' is like number of ships, it's all relative.