Year	million ton-km
1970	0.400000006
1971	0.6999999881
1972	0.6999999881
1973	0.5
1974	0.5
1975	0.400000006
1976	0.400000006
1977	0.400000006
2002	4.087
2003	3.265
2004	3.143
2005	1.202
2006	1.111
2007	2.0300000000000002
2008	0.661
2009	0.987
2010	0.022663075938342
2011	0.0951600512
2012	0.0681726118818161
2013	1.07095376052747
2014	1.75384
2015	2.30126
2016	1.441695
2017	0.876
2018	0.67645
2019	0.68860716