Pepsi Max is primarily consumed by people in Asian, European, and Australia/New Zealand markets.
While Pepsi Max was initially launched in April 1993, it wasn't introduced to the United States until 2007, where it had a different formulation. In 2016, the product in the US was rebranded as Pepsi Zero Sugar. Therefore, while the formula and branding have evolved, consumers in the aforementioned international markets continue to drink Pepsi Max.
In summary, Pepsi Max drinkers are predominantly located in Asia, Europe, and Australia/New Zealand.