Year	million ton-km
1970	13.6999998093
1971	17.2999992371
1972	18.8999996185
1973	24.6000003815
1974	33.9000015259
1975	44.7999992371
1976	53.5
1977	42
1978	37.5
1979	41.5
1980	34.5
1981	38.4000015259
1982	30.7000007629
1983	28.8999996185
1984	32
1985	30.5
1986	31.1000003815
1987	52.5
1988	55.2999992371
1989	59.7000007629
1990	57.2999992371
1991	33.2000007629
1992	28.5
1993	22.1000003815
1994	43.0999984741
2001	7.40000009536743
2010	0
2011	0
2012	0.206531325
2013	0.081984
2014	0.084444
2015	0.0858397685950413
2016	0.058456882
2017	0.228606
2018	0.915105
2019	0.7512
2020	0.962586878523834
2021	0.948713924