I mean, I guess you can be reductive about "significant" and try to dissect what it means for something to be "important", insofar as you may find yourself thinking "What *is* importance, anyway? Maybe importance isn't important at all! Wait...wait that makes no sense." and then your dick explodes, or you can just not be a robot and go with the normative understanding that ISIS has lost large amounts of influence in Iraq according to conventional thought because those large swathes of land are no longer under its thumb.