I referenced the larger volume figure in this case, since intra-entity UTXO consolidations and privacy-related hops are a long-term part of network functionality in terms of taking up some block space. That puts it a little over 1% of Fedwire, as least the last time I ran the numbers which was 2 years ago. Presumably if there are 10x as many entities using on-chain bitcoin in the future, there will be roughly 10x as much demand for intra-entity UTXO consolidation and privacy hops and such as well.
But yeah on a strictly inter-entity basis, it' s notably less than 1%.
My 2-year-old numbers:
