Ok, that was funny. You can't even mine this XRP stuff. With other words your pie chart for 'XRP Ledger' would show 100% Ripple Lab Inc. You mix things up. And yes, next time use at least a pie chart with current data...
Well, if you want to call mining a prerequisite for determining whether one could speak of centralized or decentralized, then I think we are done talking.
The hard cold fact remains that any 'decentralization' within BTC died as soon as ASICS were introduced. And honestly, I think you know this as well - but consciously decide to ignore this.
A few large mining farms in the BTC sphere working together can pretty much do what they want. If you still want to call that decentralized, go right ahead.
You brought the mining topic up to show us 'believers' how 'decentralized' your favorite altcoin is. I personally don't like the current level of
BTC mining 'centralization' or 'decentralization' but prefer it to more centralized chains (e.g. VerWuCoin) or premined business models (e.g. XRP)... Not sure what separates the last from a central bank.

If you prefer a central bank token, stay with Ripple Lab Inc.