| | Dec. 31, 1920 | Dec. 31, 1925 | Dec. 31, 1930 | Dec. 31, 1935 | Dec. 31, 1938 |
|---|
| Number of Telephones[2] | 8,133,759 | 11,909,571 | 15,187,296 | 13,573,025 | 15,761,095 |
| Number of Central Offices | 5,767 | 6,147 | 6,639 | 6,896 | 6,975 |
| Miles of Pole Lines | 362,481 | 394,529 | 428,212 | 407,454 | 399,368 |
| Miles of Wire: |
| In Underground Cable | 14,207,000 | 27,769,000 | 45,116,000 | 47,639,000 | 50,783,000 |
| In Aerial Cable | 6,945,000 | 12,835,000 | 23,777,000 | 26,425,000 | 28,072,000 |
| Open Wire | 3,711,000 | 4,339,000 | 5,231,000 | 4,562,000 | 4,590,000 |
| Total | 24,863,000 | 44,943,000 | 74,124,000 | 78,626,000 | 83,445,000 |
| Per Cent Total Wire Mileage in Cable | 85.1 | 90.3 | 92.9 | 94.2 | 94.5 |
| Average Daily Telephone Conversations:[3] |
| Exchange | 31,818,000 | 48,051,000 | 61,150,000 | 58,066,000 | 67,400,000 |
| Toll and Long Distance | 1,307,000 | 2,090,000 | 2,884,000 | 2,224,000 | 2,497,000 |
| Total | 33,125,000 | 50,141,000 | 64,034,000 | 60,290,000 | 69,897,000 |
| Total Plant | $1,373,802,000 | $2,566,809,000 | $4,028,836,000 | $4,187,790,000 | $4,489,078,000 |
| Number of Employees[4] | 228,943 | 292,902 | 318,119 | 241,169 | 257,443 |
| Number of A.T.&T. Co. Stockholders | 139,448 | 362,179 | 567,694 | 657,465 | 646,882 |