Some blockchain explorers also have a "Rich List" that will sort the list with the top holding addresses....some will provide stats according to address weights....Look at the stats in the blockchain explorer of the particular currency you're interested in comparing....There can also be several different explorers for the same currency that display alternate information....Just check out the different block explorers....you might be surprised at what you'll find!
https://bitinfocharts.com/top-100-richest-bitcoin-addresses.htmlHere's the link you just talked about. I have seen these rich lists and they're amazing.. These guys are either huge players (billionaire investors) or people who bought BTC under $1 and are now living off it. Top 1 player has a third of a billion.. However, I don't think anybody knows who these guys are. Wondering how they manage their funds..
From this chart you cannot say whether the wallet holder are still holding that coins or not because in the initial when bitcoin fell to single dollar that time lot of users who holding high bitcoins just thrown their wallet and forget it now they are searching all details and crying. So keeping this list in mind you cannot tell perfectly whether that much coin are in circulation