Year	million ton-km
1970	1.7999999523
1971	2
1972	2.0999999046
1973	2.2000000477
1974	1.7999999523
1975	1.1000000238
1976	1.1000000238
1977	1.2000000477
1978	1.2000000477
1979	1.2999999523
1980	1.5
1981	1.5
1982	1.7000000477
1983	1.6000000238
1984	2.2999999523
1985	2.2999999523
1986	2.4000000954
1987	2.5
1988	2.5
1989	1
1990	1.1000000238
1991	1.1000000238
1992	1.1000000238
1993	1.1000000238
1994	1.1000000238
1995	1.2000000477
1996	1.2000000477
1997	7.5999999046
1998	6.5999999046
1999	6.1999998093
2000	0.774
2001	0.882
2002	1.988
2003	2.078
2004	2.463
2005	2.722
2006	2.788
2007	2.867
2008	2.83
2009	2.614
2010	2.06226
2011	3.53038
2012	3.82987504054834
2013	2.861556
2014	3.90162
2015	3.3857879
2016	5.065285902
2017	4.83393550069972
2018	4.74216559835534
2019	8.30683
2020	1.242318
2021	18.36186366