Tach needle very slightly jiggling

[4D17HY4]

I've noticed that when holding a constant speed (or even in neutral), the needle on my tach doesn't just sit still - it jiggles up and down a little bit. And I don't mean a shift when the A/C kicks in with more load, these are very small movements, about 1-2 every second.

Anybody else see this happening on their car?

 

[Hilfloskind]

I see that ever so slightly every so often...barely noticeable.