why does my truck sit level?

[jb1016]

First off, I apologize, cuz I'm a freakin' noob when it comes to suspension stuff. I've got a 93 shorty, and it sits level -- 32" front, 32" rear. I like that it's level, but I want to go a little lower in the future, and all the mild kits out there are designed for a bigger drop in the rear. I'm hoping somebody can tell me why it's lower than stock in back? There's nothing back there that looks aftermarket...do the leaf springs sag over time? Is it possible that one of the leaves was taken out of each side? Or could it just be that my shocks are worn out?

Thx in advance, and sorry for the noobie questions