China produces about 150,000 metric tons annually. This is much more than the rest of the world combined producing 78% of the world’s silk.
Silk is mainly produced in the south of the Yangtze River Delta. Renowned silk producing regions are Jiangsu, Zhejiang and Sichuan provinces. Cities such as Suzhou, Hangzhou, Nanjing, and Shaoxing are well known for their silk industries.
It might have been one of the most zealously guarded secrets in history. Anyone found smuggling silkworm eggs, cocoons, or mulberry seeds was put to death.
Silk cultivation spread to Japan about 300 AD, and by the year 520, Europeans and Arabs started to manufacture silk.
According to chinahighlights.com
Mihan (Collect and edit) (World Records Union – WorldKings.org)