First pitch swing percentage

I've been working on getting some hitter statistics working with the PITCHf/x I compile (courtesy of Joe Lefkowitz's amazing site). I don't have as many metrics yet for hitters as I do for pitchers; one I've been fiddling with recently is first-pitch swing percentage. Since I don't have much more to say, here are MLB-wide leaders and trailers for first-pitch swing percentage (out of total plate appearances, minimum 200, data as of 6/21/10).

1. Vladimir Guerrero .498

2. John Buck .486

3. Jeff Francoeur .448

4. Delmon Young .443

5. Josh Hamilton .431

6. Carlos Pena .428

7. Brad Hawpe .425

8. Pablo Sandoval .424

9. Vernon Wells .424

10. B.J. Upton .412

1x. Franklin Gutierrez .046

2x. David Eckstein .057

3x. Brett Gardner .073

4x. Carlos Ruiz .074

5x. Bobby Abreu .081

6x. Luis Castillo .083

7x. Kevin Youkilis .083

8x. Dustin Pedroia .091

9x. Joe Mauer .105

10x. Ryan Sweeney .107

Gameday data is from MLB Advanced Media.