factors, check closely with the estimates of the National Bureau of Economic Research, which are based on more painstaking and more meticulous methods.
The amount of the national income, the amount received by the railways as operating revenue, the percentage thereof to the national income, the percentage of the expenditure for labor with respect to the national income, and the indicia for railway freight rates and general inflation are all shown in the next following table. The indicia for freight rates represent the average receipts per ton-mile as computed by the Interstate Commerce Commission. In the three fiscal years ending with June 30, 1915, these averaged 0.7313 c., and that is taken as the base = 100.
| Year | National income, millions of dollars |
Railway operating revenue, millions of dollars |
Percentage of national income |
Index of freight rates |
Most probable composite index | |
| Revenue | Labor | |||||
| 1916 | 45,400 | 3,597 | 7.92 | 3.23 | 96.7 | 125 |
| 1917 | 53,900 | 4,014 | 7.45 | 3.23 | 97.8 | 150 |
| 1918 | 61,000 | 4,881 | 8.00 | 4.28 | 116.0 | 165 |
| 1919 | 66,000 | 5,145 | 7.80 | 4.31 | 133.0 | 195 |
| 1920 | 72,000 | 6,178 | 8.59 | 5.11 | 143.8 | 200 |
| 1921 | 55,000 | 5,517 | 10.03 | 5.03 | 174.3 | 170 |
| 1922 | 59,000 | 5,559 | 9.42 | 4.47 | 160.8 | 170 |
The statistical exhibitions in this study reveal some very important, and even surprising, things, which may be summarized as follows:
Railway freight rates declined up to 1918 although the prices for all commodities and for labor in general were steadily rising, and in 1917 had already attained
