Hong Kong-based Top Form International, which supplies Vanity Fair, Warnaco Group, and Wacoal, has reduced its China production from 65% of total output three years ago to just over 50% now. It could drop to just one-third. Top Form is one of hundreds of textile manufacturers that have been diversifying beyond China, the world's No. 1 apparel producer. Cambodia is one popular destination. While in 2010, China produced 43.6% of rich countries' apparel imports, that number shrank to 36.8% in the first half of last year, estimates Clothesource. The stronger yuan, stricter enforcement of environmental rules, and above all rising wages are pushing production out.