Statistical expressions compute values based on a value
       expression evaluated for each record in a record stream.
       Format
       To specify the average, maximum, minimum, standard deviation, or
       total:

       { AVERAGE }
       { MAX     }
       { MIN     } value-expression [OF rse]
       { STD_DEV }
       {         }
       { TOTAL   }

       To specify the count:

       COUNT  [OF rse]

       To specify the running count:

       RUNNING COUNT

       To specify the running total:

       RUNNING TOTAL value-expression