During the Song dynasty the emperors expanded both examinations and the government school system, in part to counter the influence of military aristocrats, increasing the number of degree holders to more than four to five times that of the Tang. From the Song dynasty onward, the examinations played the primary role in selecting scholar-officials, who formed the literati elite of society. However the examinations co-existed with other forms of recruitment such as direct appointments for the ruling family, nominations, quotas, clerical promotions, sale of official titles, and special procedures for eunuchs. The regular higher level degree examination cycle was decreed in 1067 to be 3 years but this triennial cycle only existed in nominal terms. In practice both before and after this, the examinations were irregularly implemented for significant periods of time: thus, the calculated statistical averages for the number of degrees conferred annually should be understood in this context. The "jinshi" exams were not a yearly event and should not be considered so; the annual average figures are a necessary artifact of quantitative analysis. The operations of the examination system were part of the imperial record keeping system, and the date of receiving the "jinshi" degree is often a key biographical datum: sometimes the date of achieving "jinshi" is the only firm date known for even some of the most historically prominent persons in Chinese history.