In an extract from a David Ogilvy ad "How to create advertising that sells." David outlines that Ogilvy & Mather at the time had created $1,480,000,000 dollars in advertising and spent $4.9 million tracking the results. He stated in this ad that:
Over 1k+ CMO's and Marketing Directors receive our latest insights. The only way you will get these insights is because you are on the list!