KBC, I'm fairly sure the list you refer to is for drugs that received BTD and then went on to become approved drugs. I'm also fairly sure the column that says Approval Date is the date when the drugs became approved drugs.

That looks right. That FDA list says there were 225 BTD approvals to the end of 2021.  This article points out that there were 437 BTDs awarded up to about April 2021, and that about half go on to receive FDA approval.