Year	million ton-km
1970	510.50000148989994
1971	558.5000006558001
1972	677.0000036731001
1973	779.4000192435
1974	952.0000034347001
1975	972.8999977485998
1976	1085.9000085741
1977	1296.9999832662002
1978	1430.2999781519002
1979	1431.8000087737998
1980	1574.6999965905002
1981	1705.2000196575002
1982	1831.6000238432998
1983	1700.4999798311999
1984	1997.3000313418
1985	2084.8000279440002
1986	2276.1000298037
1987	2397.4999933018003
1988	2332.8999773115
1989	2600.1000050156995
1990	2727.0000172703
1991	2683.0999441592003
1992	3006.9000287203
1993	3243.2000598459995
1994	3615.4999866039
1995	3602.0000369103
1996	3511.9000796825
1997	4554.4999703915
1998	4664.7999948114
1999	4180.500075295699
2000	4618.948
2001	4170.756
2002	3925.755
2003	4028.7660000000005
2004	4657.901
2005	4535.130999999999
2006	4362.132
2007	4797.924
2008	5239.854
2009	6619.786
2010	5132.889014966706
2011	5057.610852502292
2012	5176.9798121727035
2013	6033.622146398286
2014	5976.699522045473
2015	5785.667613113582
2016	5662.617480661001
2017	6009.047768559689
2018	6356.42647479386
2019	6269.907486522583
2020	5248.581138836
2021	5760.757300659999