That's also an 18% reduction
Log probabilities (like decibans) unify this to say there is a -0.86 dB risk reduction for everybody.
https://rationalnumbers.james-kay.com/?p=306
It makes the math of combining risks easier and works the same even if we're operating near 99.999% or 0.0001%
If someone is high risk, say 20%, then an 18% drop from that is 14.4%. That may justify picking up caffeine.
But if you’re otherwise healthy, picking up caffeine has diminishing returns, and the downsides may not be worth it.