(ShareCast News) - Market research agency BrainJuicer Group returned to double-digit growth in the first half of the year, after years of "pedestrian progress", helped by the fall in the value of the pound.For the six months ended 30 June, revenue grew 12% to £13.04m, or 8% in constant currency, when compared to the same period last year, and gross profit rose by 15% to £10.68m, or 11% in constant currency.Normalised profit before tax grew 22% to £2m and reported profit before tax increased by 45% to £1.65m.Cash at period-end rose 18% to £5.18m, compared to December 2015, and the company reported it had no debt even after having returned £2.21m to shareholders by way of dividends and share buy-backs.Gross profit from the ad testing and brand tracking services, which represented 36% of the business over the past six months, increased by 59%. Over the last five years, growth in these services rose 38% in annual compound rates.Profits at the gross level for the predictive markets product, which represents 32% of the business, fell 4% due to pricing pressure, which prompted the company to develop an express version of the product.The company's other quantitative services, which collectively made up 30% of gross profit, grew 29%. The juice generation and behavioural consultancy services made up less than 2% of the business.Gross profit in the US business grew 27%, or 17% at constant currencies, and is now the company's largest market making up 41% total gross profit.Continental Europe's gross profit rebounded jummping 30%, or 21% in constant currency. Brazil's profit also grew by 21%, or 33% in constant currency.In the UK, its second largest market, gross profit fell by 2% due to sharp declines at two large clients. Excluding the two clients, UK gross profit increased 22%.There was a small decline of 5%, or 10% at constant currencies, in gross profits from Singapore and China.Founder and chief executive, John Kearon, said the business was now almost exclusively focused on its Juicy pioneering System1 research methods and quantitative market research, "enhancing our distinctiveness and ability to scale and grow revenues ahead of costs"."The strong growth in our System1 brand tracking and ad testing services has also increased the proportion of business which is ongoing in nature and therefore more stable."In October, an interim dividend of 1.1p per share will be paid, a 10% increase, which amounts to £140,000, and a special dividend of 12p per share amounting to £1.48m.Shares in BrainJuicer Group were up 6.08% to 480p at 0925 BST.