If I remember correctly, it shrank about 2 inches in length per yard.
I had torn off lengths for curtains - and I am so glad that I made them longer than I thought I would need.
I am one of those "measure before and after washing" persons . Most of the time, cottons do shrink - and usually more in one direction. So far, I have not been able to predict which way it will shrink more - lengthwise or crosswise.