Pub chain JD Wetherspoon said it had been boosted by strong trading around the fortnight of the Jubilee celebrations and during the Euro 2012 championships.The firm said the events had helped push up like-for-like sales by 6.1%, and total sales by 11.9% in the 11 weeks to 8 July 2012.In the year to date, like-for-like sales increased by 3.0%, while overall sales increased by 9.2%, the company said.It expects to report an operating margin of approximately 8.5% before exceptionals in the second half.Wetherspoon said it expected to achieve "a reasonable outcome" for the current financial year."As previously stated, the main challenges for the company, in this financial year of 53 trading weeks, have been the continuing cost pressures resulting from government legislation, including increases in excise duty, business rates and carbon tax," the company said.