Take “AFAICT” and “as far as I can tell” and do a http://www.googlefight.com/
- AFAICT: 33,100 / 324,000,000 = .000102
- FWIK: 4,490 / 1,020,000 = .004402
(But then, I interpret FWIK as “for what I know”. You’ll have to get more complex to include all the other variants.)
However, if you’re trying to use measurement to justify abbreviation – that’s a very slippery slope. Statistics will not account for class or proper use.
To my mind it’s all about understanding your audience, and statistics be damned. If you’re texting to your family or friends, you’ll just have to gather which is more appropriate – typing out a bunch of letters or communicating as curtly and efficiently as possible. Contemplating the balance is half the fun.
Publishing with abbreviations for public consumption, or to anyone you don’t know, you may inadvertently look like a child.
Just my $.02