Is HTML mail finally sufficiently ubiquitous that one can simply assume that anyone you send it to will have the ability to read it?

I'm looking for statistics on popularity of mail readers, and having a hard time finding any. Do any of you know of any?

My random wild-assed guess would be something like:

• 40% Outlook
• 30% AOL
• 25% Yahoo/Hotmail/etc
• 4% Eudora/Netscape
• 1% everything else

...but surely someone has actually studied this?

Eudora has shitty HTML support (it displays basic tags, but not tables). However, I think all the others on that list display HTML properly. (If my guesses are right, that's 95%.)

(Please note! This is not an invitation for you to tell me that you use /bin/mail in an 80x24 terminal emulator. I'm looking for numbers, not a survey of the personal preferences of power-nerds.)

Update, Jan 4: The most believable numbers I've seen are these, at clickz.com; they are approximately in line with my guesses. I think it's safe to assume that Damned Near Everybody is capable of receiving and properly displaying HTML email (though of course they may not prefer it.) Thanks to zonereyrie for pointing to that survey.