© ITU 2011 International Telecommunication Union Place des Nations CH-1211 Geneva, Switzerland All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of the International Telecommunication Union. Denominations and classifications employed in this publication do not imply any opinion on the part of the International Telecommunication Union concerning the legal or other status of any territory or any endorsement or acceptance of any boundary. Where the designation “country” appears in this publication, it covers countries and territories. ISBN 92-61-13341-X