UNCTAD uses the Hamburg Shipbrokers’ Association (formally the "Vereinigung Hamburger Schiffsmakler und Schiffsagenten e. V." or VHSS for short) as its main industry source for container ship freight prices. The VHSS maintains a few indices of container ship charter prices. The oldest, which dates back to 1998, is called the "Hamburg Index". This index considers time-charters on fully cellular containerships controlled by Hamburg brokers. It is limited to charters of 3 months or more, and presented as the average daily cost in U.S. dollars for a one-TEU slot with a weight of 14 tonnes. The Hamburg Index data is divided into ten categories based primarily on vessel carrying capacity. Two additional categories exist for small vessels of under 500 TEU that carry their own cargo cranes. In 2007, VHSS started another index, the "New ConTex" which tracks similar data obtained from an international group of shipbrokers.