Industry benchmark for converting visitors per month to impression

Is there any industry benchmark to convert visitors per month of a website that comes with Google Analytics report (or other such analytics software) to number of monthly impressions for basic understanding. I am in the midst of analytics data from a research report that reads 16,784 visitors per month of a category of website ( I need to get an idea of the impression (I know it will be rough estimate) associated with the same (16,784 visitors per month).