$aRegistrationInfo = array(
  '24hours' => $user->getCountFiltered('signup_timestamp', time() - 86400, 'i', '>='),
  '7days' => $user->getCountFiltered('signup_timestamp', (time() - (86400 * 7)), 'i', '>='),
  '1month' => $user->getCountFiltered('signup_timestamp', (time() - (86400 * 7 * 4)), 'i', '>='),
  '6month' => $user->getCountFiltered('signup_timestamp', (time() - (86400 * 7 * 4 * 6)), 'i', '>='),