Quote

"A truth whispered among animators is that 70% of a shows impact comes from the soundtrack" Michel Dougherty

Personally I believe the percentage of impact to be equal for both visual and audio. The emotion you feel when you are watching anything is hugely increased by the soundtrack accompanying it. The imagery can be anything from beautiful and moving to chaos and carnage, however I believe it to be the right soundtrack that provokes the wealth of emotions experienced.
As for the use of the word "whispered", this gives us the impression that it is a secret that animators don't want to admit. Understandably so as their job is to create the actual imagery we see before us so to admit that most of the impact comes from the music would be quite difficult for an animator. However it is the soundtrack that brings that animation to life. It is a collaboration, without the soundtrack we would not experience the amount of emotion intended and vice versa.