For your own internal purposes you can include or exclude anything you like from your stats. It might be worth presenting just the significant incidents and adding that there have been a small number of incidents where there seems to be no fault and no lessons to learn. The point of keeping stats is to drive improvement by targetting resources; if there's no improvement to be made then as long as you have a record there's no need to report them internally,

John

You should really be recording anything that might be work related even examples of what looks like carelessness. As Hilary has said, if the same stupid things keep happening there might be a link associated with some work related factor such as fatigue.  

The key when presenting information to your management to clearly classify the accidents so it is clear which are significant incidents and which are just background noise. The aim of the stats should be to learn which areas need to be prioritised: it is not about showing the world how good the business is.