Random rotation of particles without the stationary middle

I have some particles rotating around the z axis. I currently have Rotation over Lifetime set to Random Between Two constants as I want some to rotate clockwise, some anticlockwise (current values -145 to 145). But that means some will end up without rotation. Is there a way to avoid the middle ground between rotating each way? Perhaps something like 45 to 145, but randomly decide if a particle goes clockwise or anticlockwise.