Most ships are removed from the fleet through a process known as scrapping.[58] Scrapping is rare for ships under 18 years old and common for those over 40 years in age.[59] Ship-owners and buyers negotiate scrap prices based on factors such as the ship's empty weight (called light ton displacement or LTD) and prices in the scrap metal market.[60] Scrapping rates are volatile, the price per light ton displacement has swung from a high of $650 per LTD in mid-2008 to $200 per LTD in early 2009, before building to $400 per LTD in March 2010.[61] As of 2009[update], over 96% of the world's scrapping activity takes place in China, India, Bangladesh, and Pakistan.[62]