Just contract specs. As I'm sure you know, a tick is the smallest increment of price movement. An ES tick is a quarter point.
I'm not sure what trades in tenths - a tick in NQ is also 0.25 of a point, with YM 1 tick is the same as 1 point. I don't trade any others, but I'm not aware of any major indices that would allow the kind of big volume necessary where a tick is a tenth of a point.
EDIT:
Sorry, just noticed you put 'average'. Do you mean that's his average net return?