That would be a "Table Averages" group. You can add a new Group to your Hud and change it from 'Everyone' to 'Table Averages' - see this guide
for more information.
The stat in the default Table Stats group is "Live Avg Stack".
Another way to get that original group back would be to load the original "Default" profile (or if you've edited the Default profle; create a new Profile and use the 'Replace Current with Default' option in the Options button menu).
Select the 'Table Stats' group there and export it.
Then switch back to your own Profile and import what you exported.