Objective C - Where do you dealloc global static variables?

Or, what is the opposite of +(void)initialize?

Here's my situation:

I have a class Unit, whose -(id)initWithName: function takes data from a global NSDictionary, which is created lazily, defined in the Unit.m file as:

static NSMutableDictionary *unitLibrary = nil;

Where do I call [unitLibrary release]?