Year	million ton-km
1975	4.6999998093
1976	3.9000000954
1977	6.1999998093
1978	8.8000001907
1979	8
1980	8.6000003815
1981	8.8999996185
1982	8.8000001907
1983	7.5
1984	11.1999998093
1985	9.6000003815
1986	9.5
1987	9.3999996185
1988	12.8999996185
1989	14.8000001907
1990	14.8000001907
1991	15.6000003815
1992	16.1000003815
1993	14.6000003815
1994	17.2000007629
1995	18
1996	18
1997	15.6999998093
1998	13.5
1999	20.7000007629
2000	22.322
2001	21.744
2002	24.176
2003	17.071
2004	23.213
2005	21.112
2006	21.89
2007	23.069
2008	22.002
2009	19.336
2010	28.504406874
2011	32.2014362461827
2012	28.5268065062122
2013	32.728836
2014	33.402132
2015	27.3706535806214
2016	26.9017828904392
2017	29.231317078
2018	31.036317
2019	30.685844
2020	31.849211
2021	38.185378