million, respectively, an increase of 11.54%. The gross profit margin for the year ended 31 December 2018 and 2017 was 36.68% and 40.47%, respectively. The drop of gross profit margin contradicts the rise

decrease of 0.79%. The gross profit margin for the nine-month period ended 30 September 2017 and 2018 was 44.73% and 38.10%, respectively. The drop of gross profit margin contradicts the rise of the revenue