Year	US$ per liter
1992	0.335
1995	0.345
1998	0.33
2000	0.475
2002	0.41000000000000003
2004	0.625
2006	0.735
2008	0.8400000000000001
2010	0.96
2012	1.1400000000000001
2014	1.065
2016	0.69