Despite moderation in the Chinese economy, United States-based companies remain upbeat on the near-term outlook of their businesses here, according to the results of a recent survey.Over three-quarters of respondents indicated that they are optimistic about how their companies will perform over the next two years in China, the latest Business Climate Survey from the American Chamber of Commerce in China (AmCham-China) showed Friday.U.S. companies turned out strong performances in China last year, as 71 percent of respondents said they posted sales growths in 2012 and 44 percent reported better operating margins in China than the global average, according to the annual survey conducted among 325 member companies of the chamber.More U.S. businesses are oriented toward selling in the Chinese market, rather than seeing China only as a processing and export hub. The percentage of respondents who said their goal this year is to sell directly into China reached a record high of 71 percent.However, U.S. companies seem to have downsized their expansion plans. The percentage of respondents with plans to increase investment by 21 percent to 50 percent dropped from about 30 percent to 18 percent over the past four years.The results reflect a slightly more conservative business outlook amid China's focus on promoting higher-quality economic expansion in an era of rebalancing, the chamber said.Flagging exports and domestic tightening to tame property prices drove China's growth below 8 percent last year. It had stayed above 8 percent since 1999.The survey also revealed that rising labor costs and a lack of qualified employees are top concerns among respondents.AmCham-China is a non-profit organization representing the interests of over 1,000 U.S. companies and 3,500 individuals doing business in China.