Make up five 16-digit numbers off the top of your head. It takes about a minute. At the end you'll see exactly which digits you over-picked.
Two rules, and the whole thing falls apart if you break them:
Nothing identifying is recorded — just the digits, how long you took, and whether you're on a phone or a keyboard.
Type 16 digits. First digit can't be zero.
Did you use anything outside your own head for any of those — a generator, a keypad pattern, a number you already knew?
Either answer is useful. Mislabelled data is the only thing that hurts.
Your 80 digits. A true generator lands every bar near the line at 10%.