No assumption, it's based on all the available historical evidence up until this point in time.
Officially you should put a disclaimer with that...
Something like: "Past performance may not be indicative of future results. Therefore, nobody should assume that the future performance will be profitable or equal to corresponding indicated performance levels"
... o no, you're basically saying that the past performance IS perfect as a guideline for the future ... I guess it's okay than... sign me up Scotty!
I could throw another piece of historical evidence in there... they are called tulip bulbs...