This DisplayString records the date/time this bin's counters were last administratively (or automatically) cleared. Since this cumulative bin on this E1 port has no fixed Duration, ClearTime is the only anchor for how far back 'since when' the running total actually covers, so a recent ClearTime here is what would explain an otherwise surprisingly low cumulative count. For example, a ClearTime that falls in the middle of this cumulative, clear-to-clear bin's window for this E1 port warns the admin that the accompanying error-second counts only cover the remainder of that window, not the whole thing.