Calling river range stat

Hey guys!Im currently a losing player trying to improve, playing NL2 and down $15 over 16K sample!

Ive noticed one of my biggest leaks is calling on the river. Im down $18. Saw my stat in poker tracker and its 33%. Whats a good stat for calling on the river? 20-25%? I know its situation and hand dependant but as a rough guide.

Obviously I have to know when to ditch the second best hand. If a passive player is raising, (agression factor 1-2) then is good sign to fold.