Year	million ton-km
1970	1.5
1971	2.5
1972	2.7999999523
1973	2.9000000954
1974	2.4000000954
1975	2.5999999046
1976	4.0999999046
1977	27.6000003815
1978	43.0999984741
1979	33.9000015259
1980	37.5999984741
1981	43.7000007629
1982	27.6000003815
1983	17.2000007629
1984	38
1985	41.5
1986	27.7999992371
1987	25.5
1988	8.3000001907
1989	8.3999996185
1990	8.3999996185
1991	5
1992	6.8000001907
1993	10.1000003815
1994	28.3999996185
1995	48.9000015259
1996	46.5999984741
1997	47.0999984741
1998	43
1999	19.7999992371
2000	15.341
2001	13.568
2002	14.922
2003	24.522
2004	24.371
2005	25.295
2006	10.714
2007	8.718
2008	8.755
2009	6.871
2010	11.236595977
2011	17.4124617143146
2012	12.3003149495376
2013	7.993202
2014	8.78072557707694
2015	9.93479748637544
2016	9.008756313
2017	9.48554381985556
2018	13.7284774028928
2019	22.980404
2020	17.95563766
2021	20.27706066