Good enough to have passed Driver's Ed a very long time ago, although I did lose 2 points for my parallel parking job. If I live and drive long enough to have to take another road test, I'm screwed.
You might be surprised. After you've become an experienced driver, you can instinctively know how to maneuver. New drivers have to think harder. Of course, this comes from someone who hasn't needed to parallel park in many years. But I used to be pretty adequate at it.
I suppose if I was able to practice without the pressure of holding up traffic and public ridicule, I could become more adequate. I don't think I'm missing much, avoiding going downtown because of the parking situation. And my city has built some new parking garages recently, in case I do feel like going downtown.
It was not in my home state of IL. It is my current state MO. But I did not have to pass a driver's test in MO to transfer my license. And even so, you do not have to pass the parallel parking to pass the test here. I would just tell them I am not doing that part.