wrong count in group

Hi ,

I have data like below format :

empgrp   empdoj      empname    empsal     emprev

AAA      01/01/15       S              20000     3500
              03/0/15        B            30000     null

BBB       02/01/15       A           25000      null
              04/01/15       C           3500      4900

CCC      03/01/15        D           4500       4000
             05/05/15        e           6000      7000
              06/05/15        f           8000      4500

                               count  = 3 for emp rev

i am geetting count value correect if apply count in detail report.

empgrp  emp rev
A              1

B              1

C              3

tot cnt :5

for summary report getting count 3 wron value

i tried with foreach ,forall emp grp count with emp rev , but it is showing wrong count only.

please some one suggest  how to get correct count