From DHH writing for SvN
The fact is that many people simply do not contact Apple when their MacBook keyboards fail. They just live with an S key that stutters or a spacebar that intermittently gives double. Or they just start using an external keyboard. Apple never sees these cases, so it never counts in their statistics.
Head to the article and read the comments section. Ouch. Hard facts exposed. This is becoming a real monster close to the scale of the batterygate. So sad about lack of clear response and permanent solution from Apple.