Comparing other's MPG by octane rating?

[RocketFox]

Hi all,

New user here.

Loving the features so far, but wondered if there's any way to compare MPG of the same models by their octane type?

So far I've been running my vehicle exclusively on Shell V-Power 99 (UK) on the basis that the manufacturer recommends higher octane fuel and Shell allude to potentially better MPG by using V-Power.. Comparing my average MPG to others on Fuelly, I can see mine's dead centre of the bell curve. I guess it's fairly unlikely others with the same model are using exactly the same fuel as myself.

On the basis that V-Power is a considerably more expensive fuel than standard Unleaded 95RON (ignoring Shell's other claimed benefits of engine cleaning properties and just focusing on the cost-per-mile) I'm curious to discover if it's really worth the extra cost!

Thanks in advance