What is the framerate used while animating?

I cannot find any information on the framerate (fps) Titanium uses to render the frames in an animation. For example, if I am animating a box from height = 50 to height = Ti.Platform.DisplayCaps.platformHeight, I would use the following code:

$.box.animate({
    height: Ti.Platform.DisplayCaps.platformHeight,
    duration: 1000
});