Market leader Tesco's TSCO.L sales were up 3.6%, while Sainsbury's SBRY.L was up 4.5% and Asda up 5.0%. By James Davey LONDON, Sept 21 (Reuters) - Some 57% of British consumers have been severely or moderately affected by the cost of living crisis so far, and in three months that figure is expected to rise to 76%, based on data from market researcher NielsenIQ published on Wednesday. Britons are contending with inflation that was 9.9% in August and is expected to rise further this year, driven mostly by the surge in energy prices.