Year	million ton-km
1977	1.7000000477
1978	1.7999999523
1979	2
1980	2.2000000477
1981	1.8999999762
1982	1.8999999762
1983	2.4000000954
1984	2.4000000954
1985	2.4000000954
1986	2.5999999046
1987	2.7000000477
1988	2.9000000954
1989	3
1990	3.0999999046
1991	3.0999999046
1992	3.0999999046
1993	3.0999999046
1994	3.0999999046
1995	3.2999999523
1996	3.2999999523
1997	3.9000000954
1998	1.5
1999	1.6000000238
2000	1.758
2001	1.565
2002	1.737
2003	1.824
2004	2.134
2005	2.198
2006	2.286
2007	2.423
2008	2.292
2009	1.989
2010	1.619251323
2011	1.36480373536981
2012	2.78623695860264
2013	3.039168
2014	0.342349878934625
2015	0.288
2016	0.230111998
2017	0.251493238
2018	0.490188
2019	0.487101
2020	0.01184
2021	0.0021904