Since #955 and #13689 Evolution graphs show a button to switch the display of historical data by day, week, month or year, it looks like this:

The feature is a little hidden. Be great to make it easier to discover this feature.

Thoughts:

• we show the buttons always on the graph? Something like this:
  

• or maybe the current selected period could be displayed as text next to the icon at the bottom right, so it more clearly appears as clickable?