my $VARS = {
    'rows' => { 
        'category1' => [
            {'id' => 'AAA', 'delta' => '0.01%'},
            {'id' => 'BBB', 'delta' => '0.03%'} ],
        'category2' => [ 
            {'id' => 'CCC', 'delta' => '0.02%'},
            {'id' => 'DDD', 'delta' => '0.04%'} ],
     },
};

##</code><code>##

[% FOREACH item IN report.rows.category1 %]
   <tr>
     <td>[% item.id %]</td>
     <td>[% item.delta %] %</td>
   </tr>
[% END %]

##</code><code>##

[% FOREACH item IN report.rows.values %]
   <tr>
     <td>[% item.id %]</td>
     <td>[% item.delta %] %</td>
   </tr>
[% END %]