I would say most channels get 15-20% of the sub count for views per video in the first 24-48 hrs. The "hot" channels will do much better. Some channels do worse. Seems the larger the channel, the tougher it is for them (unless they are a hot channel). After the first 48 hrs, the views per hour fall off drastically, though they will always continue to get views. I also think a channel like UTG's that uploads videos about 4x a week makes it harder to keep consistent engagement, just because of the dedication it takes to "stay that tuned in".