# "Modulation" effect of collector current on DC current gain

I've found that it is typical for a BJT NPN transistor to exhibit current gain $$\h_{FE}\$$ which varies up and down as $$\I_C\$$ increases. The reason is probably trivial, but for some reason intuition tells me that $$\h_{FE}\$$ should decrease monotonically with $$\I_C\$$.

This image is taken from a 2N3904 datasheet.