Range Probability

[Frank]

You could interpret it that way. but thats why I take logs to get the linear trend. Ths is your data plotted.







When you see the log plot, It says to me you can only be confident that its really overdue ( due for a gap of 0) when its approaching a gap of 50. Hence my original suggestion of an overdue of 7.
Of course the majority of the time you can say that by 10 draws is getting a little late, and make up a rule based on whatever you think. Its a matter of personal judgement but I hope you agree that by doing this you get a picture of the probabilites and can make a more considered judgement.