Top: cumulative ZEC balance in the Ironwood shielded pool. Bottom: daily inflow and outflow lines. Ironwood is the newest shielded pool, activated with Network Upgrade 6.3 (NU6.3). Balances stay at zero until the pool begins accepting funds.
The upper panel is how much ZEC sits in the Ironwood pool; the lower is how much moved in and out each day. A balance is a stock and a flow is a rate. Reading one as the other is the mistake this chart most invites. A falling balance with healthy flow in both directions is turnover; a falling balance with no flow is abandonment. They look the same on the top panel alone.
Both sides are exact, not estimated. Value entering or leaving a shielded pool crosses the transparent turnstile and is counted by consensus, which is why these numbers can be stated precisely while nothing about the holders can be. What stays hidden is everything inside: who, how much each, and moving to whom.
The flat zero at the left is not missing data. Ironwood activated with NU6.3 and holds nothing before that, so the line begins where the pool does. Its inflow so far is dominated by migration from Orchard, tracked on the migration page.
For all pools on one axis see shielded pool balances, or net flows compared for the same question asked of direction alone.