IAS is the premier service of the government of India. There are three recruitment modes, the predominant one being via the UPSC exam annually. Some officers are also hired from the state civil services. In some cases, non-state civil service officers are selected. Two-thirds of the IAS officials are selected through the UPSC exam. The exam is held for recruitment of candidates for Indian Police Service (IPS), Indian Foreign Service (IFS) and other Group A and B central services apart from IAS.