Year	US$ per liter
1991	0.66
1992	0.6
1995	0.555
1998	0.48
2000	0.43
2002	0.53
2004	0.8200000000000001
2006	1.01
2008	1.0350000000000001
2010	1.165
2012	1.22
2014	1.1549999999999998
2016	0.88