Year	million ton-km
1970	1.1000000238
1971	3.0999999046
1972	4.0999999046
1973	3.5999999046
1974	3.4000000954
1975	4.5999999046
1976	6.3000001907
1977	6.8000001907
1978	8.1000003815
1979	8.3999996185
1980	11
1981	13.1000003815
1982	5.4000000954
1983	4.8000001907
1984	5.4000000954
1985	5.4000000954
1986	10.8000001907
1987	8.6999998093
1988	3.7999999523
1989	4.6999998093
1990	10.3000001907
1991	9.3999996185
1992	3.7999999523
1993	0.3000000119
1994	0.3000000119
1995	0.400000006
1996	0.3000000119
1997	0.3000000119
1998	0.3000000119
1999	0.3000000119
2000	0.328
2001	0.256
2002	0.248
2003	0.283
2004	0.283
2005	0.3
2006	0.324
2007	0.288
2008	0.464
2009	0.365
2010	7.52854005922458
2011	5.72301943045061
2012	2.1282547665725
2013	3.672312
2014	2.90666681323636
2015	2.54943277629794
2016	1.37789973
2017	1.236961352
2018	0.711155
2019	0.758181
2020	0.617193348
2021	13.560057648