I know a very specific use case in management consulting where hours spent by a consultant for a repetitive task (mainly report writing and source data gathering) went from on average of 40 hours to 12 hours per project. It costs the firm roughly ~$150 in token spend to save those 28 hours. They used to be roughly $200/hr (so $5k~$6k).

That's about as hard of data as you can get.