Year	million ton-km
1970	5.9000000954
1971	6.8000001907
1972	4.3000001907
1973	7.4000000954
1974	8.3000001907
1975	8.5
1976	5.6999998093
1977	5.8000001907
1978	7.8000001907
1979	8.1999998093
1980	27.7000007629
1981	31.3999996185
1982	45.7000007629
1983	43.5
1984	55.5
1985	56.9000015259
1986	34.7999992371
1987	36.7000007629
1988	38.2999992371
1989	19.1000003815
1990	13.1000003815
1991	9.6000003815
1992	9.3000001907
1993	21.7000007629
1994	25
1995	38.9000015259
1996	41.5999984741
1997	34.4000015259
1998	51.5999984741
1999	46.5
2000	42.03
2001	36.88
2002	42.717
2003	20.254
2004	22.825
2005	24.399
2006	29.001
2007	26.095000000000002
2008	25.522
2009	23.105
2010	0
2011	0
2012	0
2013	0
2018	0.066817
2019	0.031566
2020	0.024731
2021	0.026099