According to an IBM commercial: "By 2010, 30% of the data stored on the world's computers will be medical images.".
Okay, disclaimer about it being a commercial, but IBM generally knows what they're talking about.
Think about all the companies in the world that aren't medical companies. And all the data they have. And think about all the home computers, with all the pictures, and all the video. I mean just think of all the pr0n on me and Dan's computers. Times about 50,000,000 pervs worse than us. And that's just in the U.S.
End just to make sure it was worth your time to click in here, behold the mousey piano player from High School Musical (she's Russian!):