Average profit margins remained flat at 9 percent of sales in 2015 across the British optical retail sector, according to Plimsoll Publishing. For the second consecutive year, 15 percent of the opticians operating in the U.K. recorded a loss in 2015, says the market research company. They were 112 out of the 731 companies analyzed by Plimsoll. A total of 235 firms recorded a loss, with 159 of them rated as being at a high financial risk,and 70 made a loss while increasing sales. On the other hand, 375 firms were described as “exceptional” performers as they posted record profits and higher sales despite the pressures in the market.