Irn-Bru maker AG Barr achieved sales growth well in advance of the market in the first half of its financial year.Total turnover in the six months to 31 July rose 13.9% to £119.2m from £103.7m in the corresponding period of 2009. That was ahead of the guidance figure of £118m issued at the end of July, when the company revealed it was performing ahead of market expectations.The Irn-Bru brand grew revenue by 8.0%, with increased marketing investment in particular in the North of England.Barr's exotic fruit drink brand, Rubicon, continued to deliver significant growth, increasing sales by 37% in the period.The company warned that growth may slow down in the second half of the year as it is up against tougher comparatives.Profit on ordinary activities before tax, excluding exceptional items, increased by 18.8% to £16.0m from £13.5m the year before."AG Barr has delivered a strong and balanced business performance across the first half and in the second half we plan to maintain our efforts to control costs at the same time as we continue to invest in our brands and infrastructure to drive future growth," the company said."Despite poor late summer weather, trading in the first few weeks of the second half has continued to give us confidence that we will meet our full year expectations," the statement added.The interim dividend has been bumped up to 6.75p from 6.25p last year, an increase of 8.0%.