Ocado Group PLC ( LON:OCDO ) has been the fastest growing grocer in recent months, according to industry data, with J Sainsbury PLC ( LON:SBRY ) the best performing of the Big Four. Boosted by a 37% increase in sales of non-alcoholic in 'dry January' and a 14% rise in sales of meat substitutes for 'Veganuary', research by Kantar found total grocery market tills in the past 12 weeks rang 0.3% higher than this point last year. READ: Grocers suffer grim Christmas as sales growth slumps to four-year low Grocery market data was also published by Nielsen on Tuesday, showing a 0.7% in the month, with price inflation calculated at 1.6% to suggest volumes were down by around 1%.