Silkworms, which have been domesticated for generations, are incapable of surviving a natural habitat. In order to produce 1 kg of silk you need 6,000 silkworms that have consumed 200 kg of mulberry leaves. They produce a silk filament which can be up to 2 km long, although the average is 1 km. 5 to 8 filaments are wound together to produce a thread.
Today most silk production takes place in Asia. With its recent economic openness, China has become the biggest producer in the world and is increasing its production year by year. In 1996 it produced 58,000 of the 81,000 ton global production!
The appearance just after the Second World War of synthetic fibers like Nylon, which were much less expensive to produce, could have signaled the end of silk, but global demand has been upheld and is even growing as silk's appearance, charm and incredible properties make it the most sought after textile fiber.