The number of UTXOs grouped by block height. You may read this as y UTXOs have been created before x block height.

The cumulative value of UTXOs grouped by block height. You may read this as y PPC are unspent since x block height.

The cumulative value of UTXOs in a block height slice. You may read this as y PPC were last spent x number of blocks ago.

The number of UTXOs in a block height slice. You may read this as y UTXOs were most recently involved in a transaction x number of blocks ago.