hook_field_extra_fields()

Invite statistics not view in admin/config/people/accounts/display page.

/**
 * Implements hook_field_extra_fields().
 */
function invite_field_extra_fields() {
  $return['user']['user'] = array(
    'display' => array(
      'invite_stats' => array(
        'label' => t('Invite statis'), 
        'description' => t('Invite statis'), 
        'weight' => 5,
      ),
    ),
  ); 
  return $return;
}