According to a Chainalysis report a tiny amount of around 1% of transactions can fall under criminal activity.
In 2019, illicit activity represented 2.1% of all cryptocurrency transaction volume or roughly $21.4 billion worth of transfers. In 2020, the illicit share of all cryptocurrency activity fell to just 0.34%, or $10.0 billion in transaction volume. One reason the percentage of illicit activity fell is because overall economic activity nearly tripled between 2019 and 2020. 
So a tiny minority uses cryptocurrency in an illicit way, while an outstanding majority play mostly by the rules.
What is the matter then?
https://go.chainalysis.com/2021-Crypto-Crime-Report.html