I have flown EK maybe 6 times this year (lets say a total of 20 legs) and have been upgraded from business to first once.
That means I am batting at 5%, well above your predicted average!
Y to J is different than J to F.
J to F is tougher - more likely to have HVC's in J and on full fare tickets. If you are a HVC 75/100plus tier miles per annnum in Y then you may get bumped (after I/O's and Plats).
My J to F isn't great either but my Y to J this year is at 2/3 legs.