Year	million ton-km
1970	2.4000000954
1971	2.4000000954
1972	2.2000000477
1973	1.7000000477
1974	1.6000000238
1975	1.2000000477
1976	0.8000000119
1977	0.5
1978	0.5
1979	0.5
1980	0.5
1981	0.5
1982	0.6000000238
1983	0.6000000238
1984	0.6000000238
1985	0.6999999881
1986	0.8000000119
1992	15.1999998093
1993	14.1999998093
1994	14.3999996185
1995	15.3000001907
1996	16.3999996185
1997	15.3000001907
1998	13.5
1999	13.6999998093
2000	12.273
2001	7.364
2010	8.328779694
2011	9.11551389645065
2012	5.4487094452797
2013	1.19358
2014	0