Unlike Bitcoin that has a limited supply, the issuance of ethereum is capped at 18 million ethereum per year. In theory, the amount of token that will be released yearly will average to the number of tokens lost yearly due to misuse, accidental loss, and others, therefore it would reach an equilibrium.
However, from this year, 2018-2019, Ethereum will change its algorithm from Proof of Work to a Proof of stake consensus algorithm called Casper, that will affect the rate of the issuance of the token. The method of issuance and the rate is yet to be known, but Ethereum guaranteed the following, in their own words:
- The current maximum is considered a ceiling and the new issuance under Casper will not exceed it (and is expected to be much less); and
- Whatever method is ultimately picked to issue, it will be a decentralized smart contract that will not give preferential treatment to any particular group of people and whose purpose is to benefit the overall health and security of the network.