
Spent Outputs by Creation Date Bands counts the outputs consumed each day and groups them by the calendar year in which those outputs were created. Series labeled 2009, 2010 and subsequent years are absolute output counts, not BTC amounts or numbers of transactions.
A rise in an older year's series means more surviving outputs from that year were spent that day. The 2021 series peaked at about 1.28 million outputs on May 2, 2021; that peak concerns outputs created in 2021, not necessarily coins mined or investors entering in 2021.
A current-year band can include outputs recycled within hours, and one transaction may consume many inputs. Consolidations can inflate counts without comparable transfer value; compare BTC volume and the percentage version to separate output fragmentation from a broader change in spending.
No. It means the spent outputs were created in 2021. Their underlying coins may have been mined much earlier and passed through many outputs before then.
One transaction can spend multiple existing outputs as inputs. Each consumed output is counted, even when many are combined into one transaction.
A creation-year label stays fixed for an output throughout its life. A rolling age band changes as that output ages, so a calendar-year group can span more than one age band.