Fill Esoteric meter w/ # of hits or damage?

Noob question: Im trying to figure out if esterric meter fills from number of hits or amount of damage dealt

Hits from the skills that generate it. Increased by certain tripods, wealth runes and specialization

To elaborate, every skills has a specific hidden meter gain value that is not tied to damage. When hitting multiple targets only small fraction of the value will be applied per every target past the first one, suggesting very aggressive scaling.

Some skills like Esoteric Reaction, and Frost’s Call and Rime Arrow (with he appropriate tripods) generate significantly more meter than others and are typically considered builders.