I am only half serious about that....should have pointed that out. Interesting links though. Correct that not everyone with income is required to file, though they should. I did not know the income level was that high though, would have guessed half that.

Just a guess but I think that overlap is probably pretty large. I would think the majority of people who don't owe taxes are due to lower incomes who would not be required to file and that is offset with deductions....purely a guess though.