So long as there are less than 100 values a bar histogram can be drawn.

After having selected 3 zip codes the field Age was grouped into 10 groups.

The above histogram shows the frequency of the individual bars and the lower histogram shows the percentage of the current selection for numeric fields. For alpha fields you can toggle between showing the percentage of the current selection, or the percentage of each category with respect to the total for that category for the complete file.

This histogram will update dynamically if you change the selection criteria.

You can generate histograms on any field and they will dynamically respond to the change of selection criteria.