Tire wear

2003 ds. Just noticed the outside 1/3 of front driver side tire is starting to wear much more than the other 2/3 of tire. Tire pressure is 15#. It does tend to pull to the left a little but I took that for me being a bit on the hefty side in the drivers seat. Its odd that the steering wheel is also cocked to the left a little. You would think it would be cocked to the right if pulling to the left. Any idea of what would cause this and how to alleviate it.

Thanks CartTrader