Year	million ton-km
1970	6.1999998093
1971	6.5
1972	7.5999999046
1973	9.5
1974	10.3000001907
1975	10.1999998093
1976	10.6000003815
1977	11.8000001907
1978	14.3999996185
1979	14.1000003815
1980	13.8000001907
1981	12.8000001907
1982	4.1999998093
1983	4.9000000954
1984	6.5
1985	7.9000000954
1986	9.5
1987	10.3000001907
1988	13.5
1989	28.7999992371
1990	48.9000015259
1991	38.0999984741
1992	42.7999992371
1993	49.2999992371
1994	54.7999992371
1995	66.1999969482
1996	70
1997	92
1998	91.8000030518
1999	80.3000030518
2000	77.827
2001	68.514
2002	66.715
2003	70.898
2004	77.109
2005	71.284
2006	79.824
2007	83.145
2008	78.92099999999999
2009	55.475
2010	76.606040095
2011	39.4180038679561
2012	91.8311627817047
2013	97.64576278
2014	120.85182858
2015	114.791591876
2016	155.552044
2017	221.814
2018	271.488
2019	317.866
2020	140.556639
2021	215.00546