What are my odds? Description as DC

I had a recollection of seeing an exercise someone had done that assigned all our common words to state a likelihood of something happen to a percentage value - I did not find that but I did find a report with US/UK policies for communicating probability and I thought it might be useful to convert it to DCs.

Descriptor	% span	d20 span	DC
Almost no chance / remote	1 to 5	1	21
Very unlikely / highly improbable	5 to 20	4	18
Unlikely / improbable (improbably)	20 to 45	9	13
Roughly even chance / roughly even odds	45 to 55	11	11
Likely / probable (probably)	55 to 80	16	6
Very likely / highly probable	80 to 95	19	3
Almost certain(ly) / nearly certain	95 to 99	20	2

Setting this up so an average person of average stats in D&D succeeds an even chance thing 50% of the time, we anchor to DC11 for 'roughly even chance'. This makes "almost no chance" things impossible for an average person to achieve without help, tools, bless or something equivalent. Similarly, it is possible to fail an almost certain task 5% of the time. To my mind, if the dice is being rolled, there ought to be a chance of it failing - if it cannot fail, no dice should be rolled.

This also means that your average D&D character rapidly becomes a creature beyond the abilities of mere mortals in just a few levels. Given that the fraction of PC's among the populace is supposed to be small, this still makes some sense - but it gives a sense of how amazingly different a character dropping a +7 modifier onto a roll is - they will succeed at highly improbably things as often as the average person will make the even chance.

I am still seeking that original article I saw - I know I read it in 2008-2010 so it is out there somewhere. I will follow this up once I find it.

Source:

UK AND US POLICIES FOR COMMUNICATING PROBABILITY IN INTELLIGENCE ANALYSIS: A REVIEW on ResearchGate - just click download to get the pdf.