I would agree that Kim Jong himself and some high level aids know. But the rest of the country is basically brainwashed and on "lock down" from the rest of the world. I have serious doubts that the vast majority in that country has any inkling of what they don't have.
There are a lot of the populace that are trying to escape NK in any way that they can. I really think they have a pretty darned good idea that they don't have enough food.