The Ethereum staking reward rate is variable and changes based on the total amount of ETH staked. If the total amount of ETH staked is low then the reward rate will be higher, with a maximum annual reward rate of 18.10%.
As the quantity of ETH staked goes up, the staking reward rate goes down. To track the current Ethereum staking rate, visit stakingrewards.com/earn/ethereum-2-0.