Have you checked your tyres? Sounds silly, but if the car is wearing the inner edges in an extreme way there can be less resistance from the tyres and make it easier for you to turn the wheel.

Another thing to check can be the adjustment of the steering rack power head - this looks like an inward hex fitting around 25mm I.D. that pre-loads the input shaft (pinion) against the rack.

With the info you've given thats about as much as i can tell - unless someone wandered past your car while it was parked and played with your power steering pump and rack!