Last season there were 1,379 intentional walks in 2,428 games. That comes out to a little more than one IW every other game.

In a recent game a TV anouncer said "It's amazing how many times an intentional walk is followed by an unintentional walk." How amazing is it?

Walks following an intentional walk	7.4% of plate appearances
Walks at other times	7.9% of plate appearances

Not very amazing at all, based on the 2004 season. The fact of the matter is that there are actually fewer walks per plate appearance after an intentional walk than at other times.