Year	million ton-km
1970	5.3000001907
1971	6.5
1972	7
1973	7.1999998093
1974	6.6999998093
1975	4.3000001907
1976	3.5999999046
1977	4.0999999046
1978	3.4000000954
1979	4.5
1980	9.3000001907
1981	15.6999998093
1982	25.5
1983	33.2999992371
1984	30.5
1985	28.7000007629
1986	32.4000015259
1987	37.2000007629
1988	29.5
1989	17
1990	23.5
1991	27.5
1992	10.3000001907
1993	9.8000001907
1994	7.1999998093
1995	1.8999999762
1996	4.6999998093
1997	5
1998	27
1999	9.6999998093
2000	8.824
2001	2.792
2002	8.724
2003	9.996
2004	9.809
2005	10.029
2006	11.269
2007	10.036
2008	10.036
2009	7.966
2010	0
2011	0
2012	0
2013	12.1983521811429
2014	12.1983521811429
2015	24.8019639339246
2016	24.161930857
2017	22.0015460675581
2018	19.7929720673716
2019	1.84341946
2020	1.683881
2021	1.56490641