Sheep shearing, typically just calle shearing, is the process by which the woollen fleece of a sheep is removed. The person who removes the sheep's wool is called a shearer. Typically shearing occurs once per year per sheep. The annual shearing most often occurs in a shearing shed, a facility especially designed to process often hundreds and sometimes over 3,000 sheep per day.. Sheep shearing is an essential part of sheep rearing in many countries around the world. Australasia has had to discard the old methods of wool harvesting and evolve better systems to cope with the huge amounts of sheep involved. By 1915 most large sheds in Australia had installed machines, driven by steam or later by internal combustion engines. Shearing tables were invented in the 1950's, but have not proved popular, although some are still used for crutching.