That's not a "list of segments", that's a number :)
As a very simple rule of thumbs you can do this:
Total_Bytes_Used_In_Target_Segment divided by (Num_Rows * Avg_row_length)
The closer the result to 1 the more dense is your table.
The larger the result the less dense your table is.
This simple calculation will point you to your primary suspects.
Better formulas weighted by pctfree/pctused are available on the web.