Group footer
For group footer output the GroupFooter band is used. This band is positioned after the Data band. And all this is about the Data band with what the GroupHeader band is linked. Every GroupFooter band belongs to the GroupHeader band. The GroupFooter band will not be output without the GroupHeader band.
Notice. The GroupFooter band is always output before the Header band.
The report with the group footer.

The GroupFooter band is used for different information output by the group. For example, if you want to output the number of strings in a group it is enough to output the text component on the GroupFooter band. Specify the following expression in the text component:
{Count()}