Col_Pladoh said:
Only WotC can estimate the actual number based on sales of the work, Imperical evidence is useless, as not 5% of the new D&D game audience posts here or on any other website
Well, I doubt if even sales of the Epic Level Handbook are any real indicator of how many campaigns involve epic level characters. The ELH isn't even actually technically necessary to play a campaign involving epic characters - just enough is given in sources like the FRCS to run such games without that book. On the other hand, actual games invovling such high level characters seem absurdly rare. Not just on ENWorld, but other gaming websites seem to have a dearth of games involving them. On a more personal level, I know of zero people who even own the ELH, let alone who have run or played in games at that power level.
It is impossible to determine for certain, but the evidence from places like ENWorld and my own experience lead me to believe that actual epic level games are vanishingly rare. Sure, there are certainly
some people playing such campaigns, but from
Dragon letters to the editor and forum submissions in the early 80s, people were playing god-killing characters who had claimed Mjolnir, Stormbringer and the Aegis back then too.
My statements are based on the the rule books published, the contents of same, ans what I have heard imperically 
That's a dangerous set of assumptions. If one had looked at 1e in 1984 or thereabouts
as written, one would have thought it to be an almost unplayable mass of confusing and difficult rules. Sure, few people
played the game that way (discarding things like the unarmed combat rules and a host of other overly complicated elements), but
as written, they were there making the game look intensely un-user-friendly, overcomplicated, and a haven for rules-lawyers (
Knights of the Dinner Table isn't lampooning older editions of D&D by having them be plagued by a rules-lawyer like Brian by accident).
If, at the same time, one had based their opinion on what they "heard empirically" about the game (leaving aside the ill-founded and silly "satanic" attacks made by the totally misinformed), one might have thought the game to be populated by power-gaming characters who summoned fleets of Star Destroyers and legions of AT-ATs to overrun Greyhawk and thought nothing of using a
push spell to kill Thor and seize Mjolnir. One might have thought 75 foot tall mutant orcs were a regular element in the game. Looking through the published modules available at the time, one might have thought that magic items were as common as acorns and pine cones.
