A tumbler is a centralized service, different from CoinJoin protocols like Wasabi, Samourai, or JoinMarket. Thus, deposits and withdraws from Tumblers can look like small 1-input-2-ouput transactions, or they can look like batched transactions, more similar to CoinJoins, depending on the Tumbler’s design.
Combined with the fact that Tumblers operate in gray if not fully illicit legal conditions, this makes it very hard to produce data about which transactions belong to tumblers.
Measuring CoinJoin use is easier because they have many inputs and many, often equally-sized outputs.
