i don’t think that it’s proportional.
For one, a porpotional relationship has to have a proportional constant, something that is done to one x value, has to be done for all the others.
I can tell that to get from x= 30 to y=10, you have to divide by three. But seeing the other x’s and their outputs, don’t go with the equation y=x/3. so, not proportional.