In ver39.0, I have lost my display column of number of messages in each of my subfolder - How do I get this back?

When TB opens, it displays the Folder Tab. (version 39.0) To the left is a list of all my created sub folders - to the right is the list of messages from the selected folder list. Before in my list of sub folders (on the left) there was a column displayed showing how many messages were in each created folder. I no longer can see this column of messages counts. What happened? How do I get it back? Thanks, Billy D. Reagan billy@reagancpa.com