Year	million ton-km
1973	1.2000000477
1974	2.7000000477
1975	5.3000001907
1976	9.3000001907
1977	17
1978	15.1000003815
1979	19
1980	19.6000003815
1981	19.7999992371
1982	19.8999996185
1983	20.6000003815
1984	53.0999984741
1985	68.8000030518
1986	70.8000030518
1987	83.1999969482
1988	76.5
1989	84.0999984741
1990	69.5
1991	99.4000015259
1992	82.5999984741
1993	47.7000007629
1994	160.6000061035
1995	165.3000030518
1996	135.6999969482
1997	199.8000030518
1998	144.8000030518
1999	143.1000061035
2000	193.867
2001	169.602
2002	171.582
2003	175.496
2004	180.432
2005	183.493
2006	190.831
2007	89.02600000000001
2008	84.21900000000001
2009	0.013
2010	164.424638607974
2011	159.692783547366
2012	152.319036972822
2013	225.1869
2014	207.73842
2015	57.0095471847824
2016	53.97916179
2017	61.74997781
2018	50.616612
2019	168.660713625
2020	117.785203056
2021	83.737427