How do you determine what percentage of tickets have been sold in a particular game?

The % of Tickets sold on our Best Games to Play report is just an estimate, but a fairly accurate

For most states, we use this equation:
Sum of all prizes claimed for each game DIVIDED BY the SUM of all Potential prizes from the game details page.
For states that don’t publish as much data for ALL prize levels, we have to use a SUM of the top six prizes claimed divided by the sum of the potential prizes for the published prize levels.
This is why it’s only an estimate.  If we cannot get the exact number of prizes available for all prize levels OR the exact number of prizes remaining or prizes claimed, we use the data that is available.
Why do we provide it?  Customers asked for that calculation explicitly.  It helps customers realize how difficult a game might be to find in their local area.  Usually, anything above 90% Est sold, will start to become difficult to find.