Year	million ton-km
1970	7.5999999046
1971	2.0999999046
1972	0.8000000119
1973	1.1000000238
1974	13.3000001907
1975	10.5
1976	12.8999996185
1977	13.8999996185
1978	12.8999996185
1979	19.1000003815
1980	21.3999996185
1981	19.3999996185
1982	18.2999992371
1983	11.3999996185
1984	19.7999992371
1985	19.8999996185
1986	7.5
1987	8.1000003815
1988	8.8000001907
1989	11.5
1990	9.3999996185
1991	8.3999996185
1992	8.3999996185
1993	6.6999998093
1994	12.3000001907
1995	12.8999996185
1996	13.5
1997	35.4000015259
1998	15
1999	7.4000000954
2000	7.813
2010	108.019487128
2011	109.421117469991
2012	116.660723422675
2013	84.621216
2014	34.283472
2015	33.102038592
2016	29.010880897
2017	21.462556513
2018	29.5593487980126
2019	20.0142059549175
2020	19.878902393
2021	12.020124731