Costa Coffee and Premier Inn owner Whitbread shrugged off the economic difficulties said to be plaguing Britain as it upped its dividend by 17% and announced plans to step up expansion.Revenues in the year to 3 March were up by 11.5% from the previous year to £1.56bn, with underlying pre-tax profits jumping by 20.1% to £287.1m. The final dividend rises by 4.9p to 33.25p, making for a full-year dividend up 6.5p at 44.5p.Chairman Anthony Habgood said the results were achieved despite market conditions that have become increasingly difficult. Chief executive Andy Harrison said like-for-like sales growth remains positive, though at a lower level than that achieved in the fourth quarter of the year to 3 March."Despite a more challenging consumer economy, we are confident that we will continue to outperform, based on the strength of our brands and our customer propositions," he said. "Our emphasis is on giving customers value for money, winning market share and keeping a tight control of costs."Whitbread plans to add about 4,000 rooms and 14 new restaurants at Premier Inn in the current year, while Costa is to gain another 300 coffee shops, growing by 15%.