I don't think that you have any control over this. Since Qlik Sense automatically adjusts everything based on screen resolution you can't do anything. I suspect that if you expand your chart to full screen that you will see numbers at each point.
You could possibly change your Y-Axis range since all of the data is between 5,900 and 11,100. But that would not work if your data could fall outside of that.
But I think when it gets too cramped that QS just doesn't display.