There's no way to determine the total spend for specific software/technologies for Fortune 2000 companies (unless you can somehow survey them, or have an inside

There's no way to determine the total spend for specific software/technologies for Fortune 2000 companies (unless you can somehow survey them, or have an insider). So what proxy method would you use to determine that Fortune 2000 companies are spending twice as much on Splunk as they do on New Relic (for instance)?