Run this script e.g. with
10 select - 20 substr(VOLUME_NAME,1,8) Name, STGPOOL_NAME, PCT_UTILIZED - 30 from VOLUMES - 40 where - 50 DEVCLASS_NAME='TAPECLASS' - 55 and - 60 PCT_UTILIZED<$1 - 70 and - 75 STATUS like 'FILLING' - 80 order by 3 asc
If there are many such tapes you could run "MOVE DATA" to empty them by moving their content to other volumes in the same pool.
Generally you will make at least 2 collocation groups - for archives and backups
Backups best stay in automated libray for quick access (reducing expiry period if no budget for now), (old)archive tapes can be filled and taken away as needed.
As previous expert mentioned - from 2 yearly consumptions you can not make any predictions since tivoli's consumption is F+I(x) - you need 3 reference points to make any predictions.