What does "normalized" mean in this datasheet?
I think there can be a rather large variation in the gain between individual parts. A range of a 100..300 is given elsewhere in the datasheet. (page 2 in this datasheet from ONsemi)

For a particular part, the actual gain at 10 mA/25 &deg;C might be 120  and for another part it might be 150. The graph seems to be fixed so that the 25 &deg;C curve is 1.0 at 10 mA, so it would appear the other values are given in relation to that point. The absolute values aren't useful here since they might be different from part to part.

In other words, whatever the gain at 10 mA/25 &deg;C for a particular transistor, the graph tells us the gain at 1 mA should be around 0.75 times that.

(Not that this is mentioned explicitly in the datasheet, so I might be mistaken.)