I do not think a meaningful answer can be had for the following reasons:
First of all, one needs to define the word "know". What exactly do you mean by "knowing a Chinese character"? If I can recognize and sound out the character when I read, but I have never used it myself, do I know it? I suppose this would be a very passive kind of knowing. If another person knows how to write it from memory, can pronounce it and use it in a sentence, then s/he certainly knows the character better than I do. If a third person not only can do everything the second person does, but also knows the etymology, and what other characters it goes with to form words. Would all three be classified as "knowing" the character? If the answer is "yes", then it does not seem fair to the third person because clearly, s/he has a much deeper knowledge than I have. In short, there are different degrees of knowing. Before any such competition, a clear definition is needed.
Secondly, in this "competition", are you relying on people self-reporting on how many characters they know, (provided we can arrive at a clear definition of "know" in the first place)? Or is there a certain way to objectively judge and compare different people's knowledge? If it is self-reporting you rely on, then much more will come into play than just the number of characters a person knows. A person who is full of self confidence may genuinely believe and report on a greater number of characters than they actually know. In contrast, a knowledgeable yet self-doubting person may do just the opposite. And that's not even counting the people who exaggerate to impress.
Also, how often have you thought you knew something, only to discover that you don't really know it? In the area of Chinese characters, many people mispronounce, misunderstand, or misuse a character without even realizing it. In view of this, self- reporting as a basis of comparison is essentially useless.
If self-reporting does not work, then there needs to be some kind of judge or judging panel to decide how many characters a person knows. Who would qualify to be in this panel? Wouldn't this person need to know pretty much all the characters there are, since they need to decide if another person "knows" a certain character?
I think there is a reason why when you try to google, you keep getting the average number that people know.