Market Track data for the 12 months to July 2010 also revealed that the volume of duty-paid sales rose 16.5%.
RYO sales have been increasing at a steady rate for the past decade, but the latest figures were a "significant milestone for the UK RYO market," Imperial Tobacco UK public relations manager Iain Watkins said.
"We are pleased that UK retailers have benefited from the turnover generated by this segment," he added.
However, recent figures compiled by JTI reveal that sales are still a fraction of what they should be because of the prevalence of illicit products.
Of all the tobacco categories, RYO is the most susceptible to counterfeiting and smuggling, and in most parts of the UK the consumption of illicit product far outweighs the legitimate market. The north of England is the worst affected, with illicit RYO tobacco making up 76% of that consumed.