True - I tried to find an example where it was centered horizontally - but couldn't quickly. Ideally I would like this (ignore the terrible paint job and alpha channel messing things up):

https://imgur.com/B6enQhw

Where you see both volume, distribution, percent, as well as the trendline (white) where you can see how the distribution changes - how the total count changes, and easily understand any data point at any given spot.