Not sure about data rate for running jobs, but you might want to look at jobquery:

bash-3.00$ jobquery -i - <
> . type:session info;completed: 0;
>
> print
>
> EOF

type: session info;
                 client name: myserver;
                   completed: 0;
           compression ratio: 0;
                current pool: BackupHMR;
    current read/write total: 118945124;
               device family: tape;
                 Device path: /dev/UOL/HMRdrive6;
                 device type: LTO Ultrium-2;
        extended information: ;
     Jobid from session info: 6549881;
      number of volumes used: 5;
          recover file count: 0;
          recover file total: 0;
              savegroup name: Myserver_a_CMR;
                  saveset id: \
4ac2f791-00000006-06014392-4d014392-09020014-4fdcd006;
                saveset name: "T:\\";
            Session end time: 1291964984;
                  session id: 98515;
                Session mode: 0;
          Session start time: 1291962408;
total amount to be read/written: 0;
        total volumes needed: 0;
               transfer rate: 0;    *** Don't think this is populated until completion ***
                 volume name: HB0253;

HTH

Will