The daily number of ETH deposited into the Beacon chain address versus the number of ETH withdrawn from the Beacon chain. Withdrawals were enabled on April 12th with the launch of the Shapella upgrade.
Note: For locking you also will need to factor in a 2% Protocol Fee (0 ACS)
If you elect to lock your ACS tokens with The Block, you acknowledge and agree that you will be subject to the terms and conditions of your third party digital wallet provider, any applicable terms and conditions of the Access Foundation, and any applicable terms and conditions of The Block shall have no responsibility or liability in connection to the provision, access, use, locking, security, integrity, value or legal status of your ACS Tokens or your digital wallet, including any losses associated with your ACS tokens. Locking your ACS tokens with The Block is at your sole risk.