Year	million ton-km
1974	2.2000000477
1975	4
1976	6.8000001907
1977	8.1999998093
1978	9.6000003815
1979	14
1980	26.2000007629
1981	21.3999996185
1982	21.6000003815
1983	23.7999992371
1984	30.7000007629
1985	32.5999984741
1986	31.3999996185
1987	31.5
1988	33.9000015259
1989	40
1990	44.2999992371
1991	51.2000007629
1992	69.8000030518
1993	88.1999969482
1994	122.1999969482
1995	132.8000030518
1996	105.8000030518
1997	99.5
1998	110.3000030518
1999	126.4000015259
2000	152.145
2001	143.092
2002	130.409
2003	189.972
2004	235.186
2009	39.196
2010	106.579
2011	171.732
2012	240.695
2013	251.141
2014	291.939
2015	412.234008
2016	425.202175
2017	434.92173
2018	510.425983
2019	566.923
2020	51.918137
2021	254.45727