This read-only Counter64 counts the total IGMP leave messages received on this PM instance. Comparing Leaves against Joins over the same bin shows whether multicast group membership on this port is growing or churning, which matters for capacity planning on a video-heavy access node; because it is drawn from this instance's running statistics bin, it behaves like a long-running total rather than a rotating window, so admins baseline against it instead of expecting it to reset daily. On a subscriber-facing IPTV access port, a count of 2,844 over the current statistics window is the kind of number an admin would trend against the join/leave rate on the same port to judge whether it's normal channel-surfing or an anomaly worth a closer look.