1 YSHIFT
  Syntax:   YSHIFT id1 [:id1n] [&idb1] id2 [:id2n] [&idb2]
            [shift]
   where:   id1    is the input histogram identifiers
            idb1   is the (optional) input secondary identifiers
            id2    is the output histogram identifier
            idb2   is the (optional) output secondary identifier
            shift  is the amount to shift the y-axis by

  Shifts the y-axis of a 2-D plot, or the bin contents or point values
  of a 1-D plot by `shift'. This is useful if you need to modify the
  bin contents of a complete plot by the same amount.

