Scroll or pinch to zoom in on a year/month, drag to pan, or hold Shift and drag to box-zoom a range. "Total" and "Reserved" are flat reference lines at today's value — APNIC's data has no historical record for those categories. "Available" is derived (today's total minus cumulative delegations up to that date minus today's reserved), so its downward slope reflects real delegation history even though the endpoints are today's figures.