Euro zone Sept retail sales much weaker than expected BRUSSELS (Reuters) - Euro zone retail sales were much weaker than expected in September, data showed on Wednesday, and the monthly August rise was revised downwards, pointing to soft household demand in the third quarter. The European Union's statistics office said retail sales in the 18 countries sharing the euro fell 1.3 percent month-on-month in September for a 0.6 percent year-on-year rise. Economists polled by Reuters had expected a 0.8 percent monthly fall and a 1.2 percent year-on-year rise. Eurostat also revised downwards the August monthly rise to 0.9 percent from the previously reported 1.2 percent and confirmed the 1.9 percent annual increase. Retail sales are a proxy for household demand and underline the forecast from the European Commission that the euro zone economy will stagnate quarter-on-quarter in the July-September period after expanding 0.3 percent in the first quarter and 0.1 percent in the second. Reporting By Jan Strupczewski; editing by Adrian Croft