| Revenue | 31/12/2018 | 31/12/2017 | 31/12/2016 | 31/12/2015 |
| Total revenue | 21,025,200 | 22,820,400 | 24,621,900 | 25,413,000 |
| Cost of revenue | 10,239,200 | 12,199,600 | 14,417,200 | 15,623,800 |
| Gross profit | 10,786,000 | 10,620,800 | 10,204,700 | 9,789,200 |
| Operating expenses |
| Research development | - | - | - | - |
| Selling general and administrative | 2,200,200 | 2,231,300 | 2,384,500 | 2,434,300 |
| Non-recurring | - | - | - | - |
| Others | 6,700 | -2,800 | -2,800 | -2,800 |
| Total operating expenses | 12,446,100 | 14,428,100 | 16,801,700 | 18,058,100 |
| Operating income or loss | 8,579,100 | 8,392,300 | 7,820,200 | 7,354,900 |
| Income from continuing operations |
| Total other income/expenses net | -763,000 | 181,200 | -954,200 | -799,200 |
| Earnings before interest and taxes | 8,579,100 | 8,392,300 | 7,820,200 | 7,354,900 |
| Interest expense | -981,200 | -921,300 | -884,800 | -638,300 |
| Income before tax | 7,816,100 | 8,573,500 | 6,866,000 | 6,555,700 |
| Income tax expense | 1,891,800 | 3,381,200 | 2,179,500 | 2,026,400 |
| Minority interest | - | - | - | - |
| Net income from continuing ops | 5,924,300 | 5,192,300 | 4,686,500 | 4,529,300 |
| Non-recurring events |
| Discontinued operations | - | - | - | - |
| Extraordinary items | - | - | - | - |
| Effect of accounting changes | - | - | - | - |
| Other items | - | - | - | - |
| Net income |
| Net income | 5,924,300 | 5,192,300 | 4,686,500 | 4,529,300 |
| Preferred stock and other adjustments | - | - | - | - |
| Net income applicable to common shares | 5,924,300 | 5,192,300 | 4,686,500 | 4,529,300 |