26. | Cost of sales |
| | 2017 | | 2016 | | 2015 | | |||
Variable costs | | | | | | | | | | |
Imported products (1) | | | 11,637,419 | | | 12,049,477 | | | 12,935,878 | |
Depreciation, amortization and depletion | | | 5,765,186 | | | 5,333,245 | | | 5,166,455 | |
Purchases of hydrocarbons - ANH (2) | | | 4,338,576 | | | 3,178,199 | | | 3,741,010 | |
Purchases of crude in association and concession | | | 2,240,704 | | | 1,517,829 | | | 1,928,938 | |
Process materials | | | 889,122 | | | 608,535 | | | 366,454 | |
Hydrocarbon transport services | | | 665,714 | | | 783,307 | | | 1,380,733 | |
Electric energy | | | 561,424 | | | 618,675 | | | 424,920 | |
Purchases of other products and gas | | | 488,056 | | | 519,884 | | | 703,163 | |
Taxes and contributions (3) | | | 449,959 | | | 478,332 | | | 481,029 | |
Services contracted in associations | | | 195,689 | | | 305,326 | | | 563,032 | |
Others (4) | | | (663,916) | | | (432,694) | | | (322,547) | |
| | | 26,567,933 | | | 24,960,115 | | | 27,369,065 | |
Fixed costs | | | | | | | | | | |
Depreciation and amortization | | | 2,366,849 | | | 2,050,739 | | | 1,433,263 | |
Maintenance | | | 2,038,970 | | | 1,998,128 | | | 2,334,130 | |
Labor costs | | | 1,815,213 | | | 1,571,511 | | | 1,542,701 | |
Services contracted | | | 1,414,056 | | | 1,083,176 | | | 1,301,094 | |
Services contracted in associations | | | 1,008,336 | | | 1,260,470 | | | 1,415,422 | |
General costs | | | 510,128 | | | 383,842 | | | 461,994 | |
Materials and operating supplies | | | 468,205 | | | 333,258 | | | 435,238 | |
Taxes and contributions | | | 343,505 | | | 391,032 | | | 461,624 | |
Hydrocarbon transport services | | | 333,671 | | | 157,463 | | | 147,733 | |
Non-capitalized costs of projects | | | 41,459 | | | 61,689 | | | 92,252 | |
| | | 10,340,392 | | | 9,291,308 | | | 9,625,451 | |
| | | 36,908,325 | | | 34,251,423 | | | 36,994,516 | |
(1) | Imported products correspond mainly to diesel fuel and diluent to facilitate the transport of heavy crude oil. |
(2) | Corresponds to purchases of crude oil by Ecopetrol from the National Hydrocarbons Agency (ANH) derived from national production, both of the Group in direct operation and of third parties. |
(3) | Includes gas royalties paid and carbon tax. |
(4) | Corresponds to the capitalization of production costs to inventory. |