Year	million ton-km
1970	3.0999999046
1971	3.7000000477
1972	4.1999998093
1973	5.1999998093
1974	6.5999999046
1975	7.1999998093
1976	9.1000003815
1977	9
1978	11.1999998093
1979	12.3000001907
1980	12.8999996185
1981	14.1999998093
1982	15.8999996185
1983	28.2000007629
1984	14.8999996185
1985	21
1986	7.6999998093
1987	13.3000001907
1988	13.8999996185
1989	23.1000003815
1990	14.6000003815
1991	24.2999992371
1992	20.2000007629
1993	21.2999992371
1994	24.2000007629
1995	21
1996	16
1997	16.7999992371
1998	18.7999992371
1999	15.3999996185
2000	12.647
2001	18.346
2002	17.89
2003	19.091
2004	21.44
2005	31.624
2006	23.694
2007	16.572
2008	16.985
2009	4.317
2010	15.906
2011	14.826
2012	14.926
2013	17.5024186277313
2014	21.6623331878
2015	21.9016451671492
2016	21.591025
2017	24.80375
2018	28.28048
2019	25.641745
2020	15.638799
2021	12.694836