Month Millions Of Net Ton-Miles 1920-01-01 888.000 1920-02-01 836.000 1920-03-01 945.000 1920-04-01 834.000 1920-05-01 867.000 1920-06-01 880.000 1920-07-01 888.000 1920-08-01 834.000 1920-09-01 881.000 1920-10-01 801.000 1920-11-01 767.000 1920-12-01 731.000 1921-01-01 664.000 1921-02-01 618.000 1921-03-01 636.000 1921-04-01 531.000 1921-05-01 424.000 1921-06-01 424.000 1921-07-01 481.000 1921-08-01 595.000 1921-09-01 625.000 1921-10-01 623.000 1921-11-01 623.000 1921-12-01 563.000 1922-01-01 545.000 1922-02-01 568.000 1922-03-01 670.000 1922-04-01 537.000 1922-05-01 642.000 1922-06-01 579.000 1922-07-01 601.000 1922-08-01 635.000 1922-09-01 652.000 1922-10-01 682.000 1922-11-01 683.000 1922-12-01 615.000 1923-01-01 703.000 1923-02-01 668.000 1923-03-01 777.000 1923-04-01 722.000 1923-05-01 772.000 1923-06-01 740.000 1923-07-01 702.000 1923-08-01 715.000 1923-09-01 725.000 1923-10-01 801.000 1923-11-01 764.000 1923-12-01 682.000 1924-01-01 654.000 1924-02-01 779.000 1924-03-01 817.000 1924-04-01 764.000 1924-05-01 834.000 1924-06-01 714.000 1924-07-01 788.000 1924-08-01 719.000 1924-09-01 784.000 1924-10-01 834.000 1924-11-01 764.000 1924-12-01 718.000 1925-01-01 762.000 1925-02-01 726.000 1925-03-01 800.000 1925-04-01 736.000 1925-05-01 775.000 1925-06-01 718.000 1925-07-01 771.000 1925-08-01 696.000 1925-09-01 773.000 1925-10-01 806.000 1925-11-01 749.000 1925-12-01 714.000 1926-01-01 722.000 1926-02-01 741.000 1926-03-01 868.000 1926-04-01 762.000 1926-05-01 385.000 1926-06-01 640.000 1926-07-01 598.000 1926-08-01 584.000 1926-09-01 646.000 1926-10-01 673.000 1926-11-01 654.000 1926-12-01 671.000 1927-01-01 733.000 1927-02-01 736.000 1927-03-01 879.000 1927-04-01 783.000 1927-05-01 845.000 1927-06-01 766.000 1927-07-01 763.000 1927-08-01 767.000 1927-09-01 789.000 1927-10-01 814.000 1927-11-01 804.000 1927-12-01 706.000 1928-01-01 705.000 1928-02-01 746.000 1928-03-01 822.000 1928-04-01 707.000 1928-05-01 794.000 1928-06-01 760.000 1928-07-01 743.000 1928-08-01 747.000 1928-09-01 753.000 1928-10-01 824.000 1928-11-01 788.000 1928-12-01 691.000 1929-01-01 746.000 1929-02-01 664.000 1929-03-01 765.000 1929-04-01 820.000 1929-05-01 829.000 1929-06-01 778.000 1929-07-01 819.000 1929-08-01 794.000 1929-09-01 798.000 1929-10-01 888.000 1929-11-01 829.000 1929-12-01 723.000 1930-01-01 794.000 1930-02-01 738.000 1930-03-01 815.000 1930-04-01 751.000 1930-05-01 815.000 1930-06-01 689.000 1930-07-01 751.000 1930-08-01 673.000 1930-09-01 729.000 1930-10-01 810.000 1930-11-01 704.000 1930-12-01 652.000 1931-01-01 669.000 1931-02-01 620.000 1931-03-01 693.000 1931-04-01 671.000 1931-05-01 656.000 1931-06-01 672.000 1931-07-01 693.000 1931-08-01 615.000 1931-09-01 671.000 1931-10-01 731.000 1931-11-01 671.000 1931-12-01 633.000