^^redacted‌, great question. This might not be available via SF but we can help you offline if needed. We have two levels of annual revenue depending on corporate structure, and if they are linked together. When businesses have corporate linkage (think HQ, SubHQ, Branch), we will have both location annual revenue, and corporate annual revenue (which is a roll up of all locations). Unless the company is public or required to file an annual report, annual revenue will be modeled. The model used is created by the department of commerce and is updated every two years. The model suggests a revenue per employee, based on the primary line of business (industry). Since we telephone verify number of location based employees, we take the number of employees at that location and multiply by the revenue per employee number from the DoC. Employee size changes fast which is why we call and verify changes 1-4 times per year, depending on volatility of the industry. Another tip is to remove any corporate linked companies and focus on only single location, sole proprietors. This filter will likely lead you down the right path and help you avoid those larger linked companies. Let me know if that's helpful.

^redacted‌ happy to chat, my database of 270M+ orgs (people data, news data, etc) might be able to help.