Retail sales in Germany, which account for around 20 percent of gross domestic product (GDP), continued to stagnate in the third quarter, data showed on Tuesday, boding ill for the long-hoped-for pickup in domestic demand in the eurozone's biggest economy. German retail sales edged up by 0.1 percent in the period from July to September compared with the previous quarter after slipping by 0.1 percent in the preceding two months, data published by the federal statistics office Destatis showed. In September alone, retail sales were down by 0.4 percent from August, nearly negating the 0.5 percent increase seen the previous month. Including auto sales and service station sales, retail sales were unchanged in price-adjusted terms in the third quarter compared with the first and second quarters, separate data compiled by the Bundesbank showed. Retail sales account for around 35 percent of private consumption in Germany, which itself accounts for 57 percent of general GDP in Germany.