By Sarah Marsh BERLIN (Reuters) – The proportion of German firms exiting the Chinese market or considering doing so has more than doubled to 9% in the past four years, according to a survey by the German Chamber of Commerce in China. The survey highlights the challenges faced by German companies operating in China, including increased competition from local companies, unequal market access, economic headwinds and geopolitical risks, the chamber said. “Last year was a reality check for German companies operating in China,” said Ulf Reinhardt, chairperson of the chamber for southern China. Some …