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	88.0999984741
1994	122.0999984741
1995	132.8000030518
1996	105.8000030518
1997	96.5999984741
1998	104.5
1999	206.6999969482
2000	244.07
2001	256.817
2002	305.484
2003	276.42
2004	469.19
2005	869.582
2006	888.498
2007	1292.746
2008	1639.146
2009	2276.378
2010	2945.787
2011	3637.131
2012	4306.922
2013	4960.582
2014	5993.108
2015	7563.30739
2016	9206.16533
2017	10970.08988
2018	12666.7094
2019	12739.81097
2020	13543.50932
2021	15861.65425