The total number of spent outputs that were created between 1 month and 3 months ago.

This is the Point-in-Time (PiT) variant of Spent Outputs 1m-3m. PiT metrics are strictly append-only and their history is immutable. The historic data does not necessarily reflect the best current knowledge, but the information at the time when a data point was first computed. PiT metrics are ideal candidates for applications in model backtesting and related quantitative purposes. Read our article on PiT metrics for more information.