By Tom Bergin LONDON (Reuters) – Google has said its UK sales hit $5.64 billion in 2013, a rise of 16 percent on the previous year — its lowest growth rate in three years. Britain is Googles biggest overseas market and the only one for which it breaks out separate sales figures and in recent years the discrepancy between the companys high UK revenues and low tax bill have prompted criticism from politicians. Google declined immediate comment on the UK sales figures. Figures in Googles 10-K annual report filed on Wednesday showed UK sales growth slowing from 20 percent in 2012 and 22 percent in 2011.