Adapting the number of columns in a SSRS 2012 chart

Hi,

in a my SSRS 2012 report I've created a dataset to extract the TOP 20 amounts. I've created a stacked column chart and I've put the amounts as a value. But I can see only ten columns respect to 20 amounts.

Now, how can I adapt the chart visualization in order to show all 20 columns?

Thanks