A statistical volume is a calculation that shows the number of volumes directly associated with the current version of a data set. For this calculation, GFTAVMA divides a volume equally among the number of data sets or partial data sets residing on that volume.
Statistical volumes reflect only the volumes that contain the latest version of the data set. On the other hand, statistical mounts reflect all the mounts attributed to a data set during the reporting period. In this sense, the data set is a cumulative value. See Statistical Mounts for information on statistical mounts.