i dont get the question tbh
first of the %, 5% of what, killed creatures? ped rotated? (each 50000 ped a 5% hof?) etc. etc.
generally the hof likelyhood depends on the cost of the task you do
if you hunt dasplator day and night for godknowshowmuch money it needs to kill them, you are more likely to hof than when you hunt say exas or something with waaaaaay less HP
or when you craft oreamps like mad you are more likely to hof than when you craft filters
neither means you are on profit in the end though
and i dont think you can give a firm answer on that either, except you keep good records about what you do, say you track all your hunts, etc. and may see a pattern