Are we decentralized yet?

This is the app: https://bitcoinera.app/arewedecentralizedyet/

Is this accurate? Where can we find this information?

I am particularly curious to find out about # of entities in control of >50% of voting/mining power and % of money supply held by top 100 accounts for BTC and ETH, but I don't know where to find it. Any help will be appreciated.