Chapter 2 - Set Theory - 2.1 Basic Set Concepts - Exercise Set 2.1 - Page 59: 107

{Australia, Unites states, United Kingdom, Switzerland,Ireland}

In the graph, Australia, United States, United Kingdom, Switzerland,Ireland are having used marijuana at least 8% and at most 18% Australia = 18% United States = 12.3% United Kingdom = 9% Switzerland = 8.5% Ireland = 8% So, {Australia, Unites states, United Kingdom, Switzerland,Ireland}