Porkies about Portman?

Fox Searchlight maintains that Natalie Portman did most of the dancing in Black Swan. Sarah Lane, however, of the American Ballet Theatre claims that only five per cent of the full body shots are Natalie.  All the other shots in the film are of Sarah, the body double.  And Benjamin Millepied claims that 85 per cent of the dancing is by his fiancee Natalie.   Someone's telling porkies.