I've tried searching Google/going through the D3 gallery to find the name of this type of chart, but I've had no luck so far. As far as I can see it is an area chart with both age and year plotted on the x axis. Does anyone know the name? And if possible a tutorial/example for Excel or even D3.js.
Edit - I think the only way to do this in Excel might be with small multiples, but if there is a 'proper name' for this chart, I'd still appreciate it.
Source: The Coalition in 163 charts