Fade out on every keyframe

Another newbie question.

Tried this expression on a layers opacity:

d = Math.abs(time -transform.position.nearestKey(time).time);

easeOut(d, 100, 0)

The idea was to make the layers opacity go from 100% to 0 on every keyframe.

What actually happens is the opacity goes down to 36% in the middle between two keyframes, then goes up to 100 again.