| (23) | Costs and expenses by nature |
| | | 2017 | | 2016 | | 2015 | | |||
| Cost of sales | | $ | 47,502,959 | | | 42,635,071 | | | 36,847,508 | |
| General, selling and administrative expenses | | | 5,423,379 | | | 4,847,858 | | | 4,323,374 | |
| Total costs and expenses | | $ | 52,926,338 | | | 47,482,929 | | | 41,170,882 | |
| | | | | | | | | | | |
| Inventory consumption | | $ | 37,567,550 | | | 34,018,493 | | | 28,877,468 | |
| Wages and salaries | | | 6,605,584 | | | 5,971,382 | | | 5,127,750 | |
| Freight | | | 4,176,508 | | | 3,712,349 | | | 3,394,780 | |
| Maintenance | | | 1,471,392 | | | 1,292,763 | | | 1,166,326 | |
| Other utility expenses | | | 1,334,339 | | | 1,005,570 | | | 1,020,610 | |
| Depreciation | | | 1,075,788 | | | 925,748 | | | 769,270 | |
| Leases | | | 416,437 | | | 403,116 | | | 359,749 | |
| Other | | | 278,740 | | | 153,508 | | | 454,929 | |
| Total | | $ | 52,926,338 | | | 47,482,929 | | | 41,170,882 | |