Display count sum in a group header(Jasper Report)

My code:

 1 <variable name="Chart" class="net.sf.jasperreports.engine.JRRenderable" calculation="System"/>

 2     <variable name="Counts" class="java.lang.Integer" resetType="Group" resetGroup="BgCheckOverallStatusGroup" calculation="Count">

 3         <variableExpression><![CDATA[$F{personUniqueID}]]></variableExpression>

 4         <initialValueExpression><![CDATA[0]]></initialValueExpression>

 5     </variable>

 6 

 7 ...

 8 

 9 <groupHeader>

10             <band height="15">

11                 <textField evaluationTime="Group" evaluationGroup="BgCheckOverallStatusGroup">

12                     <reportElement uuid="f5c1b936-6a8a-4b51-ba5f-ed69343f34f4" style="Arial_Bold" x="508" y="0" width="46" height="15" forecolor="#000000"/>

13                     <textElement textAlignment="Left" verticalAlignment="Middle"/>

14                     <textFieldExpression><![CDATA[$V{Counts}]]></textFieldExpression>

15                 </textField>

16             </band>

17         </groupHeader>