In the second edition of the book "Petroleum Refinery Process Economics" (2000), author Robert Maples notes that U.S. refineries rank highest in complexity index, averaging 9.5, compared with Europe's at 6.5. The Jamnagar refinery belonging to India-based Reliance Industries Limited is now one of the most complex refineries in the world with a Nelson complexity index of 14. The new refinery began trial production on December 25, 2008. The former BP Texas City, Texas refinery, newly acquired by Marathon Petroleum as their Galveston Bay Refinery has a Nelson complexity index of 15.3 in 2013.