What is the word used to describe the increase of several things but of the same ratio?

For example, say you have a big streamer, medium streamer, and little streamer on Twitch livestreaming a new game, and some country unbans the site's access. The influx of new people that flock to the big streamer would be far greater than that which would flock to the medium streamer, and the medium's streamer's gain would be greater than the little streamer but less than the big streamer, and so on with the little streamer. It's ike it aligns with the ratio you would expect. There must be a word for this. Is it proportionality?

Thanks!