Raw stats give (usage of this Pokémon in battle)/(usage of all Pokémon in battle).
Full team method gives (usage of this Pokémon on teams)/(usage of all Pokémon on teams).
I don't know how Antar does it but assuming it's accurate it makes sense that Hippopotas would go down in usage. Especially considering it's essentially only used when its ability to set up Sandstorm for the rest of the team is needed.
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