The average amount advertisers pay Google anytime someone clicks their own ad for this keyword. The default is “broad match”costs, but exact match and phrase match are available when you click through on the keyword....
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​How do we get it? By experimenting in the Google Traffic estimator, we find the cost per click that comes closest to our target Avg. Ad Position of 2.0.

When we include this stat alongside organic rankings, it is to be a comparison of how much this keyword would cost in AdWords.
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