Does the study refer to BTC only? Would be interesting to know because there is also Monero and other coins which are more likely to be used by criminals. Ca Chainalysis do anything about those anonymity coins?
They claim the study refers to crypto currencies in general, between 2017-2020 time period. So I believe monero and other coins are included.
Talking about bitcoin specifically the percentage of illegal activity is even lower, reaching to 0,5% compared to the total volume of transactions.