The graph shows a steady fall in the volume of additional water needed to produce 1 litre of bottled water. In 2001 an additional 1.5 litres was required. In 2002 that figure was down to 1.3 litres. In 2003 1.2 litres was needed and in 2004 1.1 litres. In 2005 just 1 litre of additional water was needed.