In a membership report, there are two distinct columns for Plan and Latest Plan. Choosing the right one can help you obtain the data you need.
The Plan column only looks at a person's current membership status. If someone is expired, they don't currently have a plan, so that field will be blank. Only active members will have a value in this column.
The Latest Plan column contains the plan that has recently expired for your expired members, as well as the active plan for all your active members. Therefore, anyone who has ever had a plan will have a value in this column.