Only around 800 US users per year comply with Internal Revenue Service (IRS) demands to report Bitcoin earnings, it has emerged.

In documents filed by the tax authority on Thursday, data shows the number of “honest” US users signaling “property description likely related to Bitcoin” on tax form 8949 is actually falling, Fortune reports.

The IRS submitted the documents as part of its ongoing investigation into Coinbase, with which it has battled since last year over allegations its user tax policies are insufficient.

Coinbase refused to allow sweeping inspections of its transaction records, with the IRS subsequently taking legal action in March to enforce its right to carry them out.

“Coinbase remains concerned with the indiscriminate and over broad scope of the government’s summons and we have produced no records under the summons,” the exchange said in a statement about the latest developments.

It added that its dedicated legal team was in the process of reviewing the IRS motion.

Coinbase is the focus of tax authority interest principally due to its size and longevity on the market. Having operated from a time when Bitcoin was worth a fraction of its current value, the holdings of a potentially sizeable number of people could have attracted considerable capital gains and associated tax obligations.