This is the percentage of auctions in which you’d like to outrank the benchmark domain.
Example: Let’s say that another domain, example.com, has ads that are often displayed above yours or display when your ads do not. In other words, their ads are outranking your ads. So if you wanted to outrank example.com’s ads in 80 out of every 100 auctions, you’d set your target outranking share to 80%.
Keep in mind: The higher your target outranking share, the more budget you’re likely to need to support the strategy.