I can sortof understand the reasoning behind people that say "each roll is unique". That is true.
But the rules of averages say that if I have a 50% chance of doing something, and I try to do it 1000 times, I should succeed at around 500 of those attempts.
Now, people that jump in and only try to make 5 of an item are not going to have a very accurate picture, since all 5 of those attempts could fail at 50%.
But if they actually had enough resources to attempt another 95 times, 'on Average' they will succeed at around 50 of them.
Averages are calculated over time, with a boatload of repetition.
As Orth's chart shows, each number from 1 to 20 has received around the same number of 'hits' on average since the chart was implemented.
Sure, there is a little variation, but it all balances out in the end.
