The Vulture have put a lot of effort into their list of the 100 Most Valuable Movie Stars. They came up with a system to determine star traits like bankability, magazine covers, likeability and critical heat etc. Once they had those values they came up with a method to weight and average everything out for the final list.
Natalie is 35th on the main list, the 8th highest woman. She’s 50th on the studio favourites list, probably hampered by her hopping from genre to genre. She’s 10th on the tabloid targets list, 61st on the international stars list and 24th on the most respected list.
Check out The Vulture’s explanation for the list criteria here, and the full list (click Natalie for a bigger writeup) here.