Game List | right-click | Statistics > Length
The length statistic shows the number of moves per game.
The maximum game length is 150. The average game length is displayed. When a game has 50 white moves and 49 black moves, the game length is rounded up to 50 moves.
Select - (or press -) to view fewer lengths.
Select + (or press +) to view more lengths.
If not all lengths are visible you can select < (or arrow left) and > (or arrow right).