Uyghur migration to Kyrgyzstan can be analysed in three waves. The first wave began in the late 19th century. Some Uyghurs from Kashgar came with the Dungans to the Ferghana Valley in the aftermath of the 1862–1877 uprising in Northwest China; the total number to settle there (including both Uyghurs and Dungans) was about 7,000 people, according to contemporary Russian reports. Later, in the early 20th century, Uyghurs, Dungans and Chinese alike came as migrant workers to find employment in coal mines and cotton mills. The second wave consists of those who fled Xinjiang after the People's Republic of China established control in the area or during the hardships of the Great Leap Forward and the Cultural Revolution. The people in this second wave tend to be connected to the political and intellectual elite of the Second East Turkestan Republic and accordingly sometimes look down on the migrants who came before or after them. The 1979 Soviet census found 29,817 Uyghurs in the Kirghiz Soviet Socialist Republic, making up 0.8% of the population. Their numbers continued to grow in the following decade; the 1989 census found 36,779 (0.9%). The third wave of migration consists of sojourners, PRC citizen traders of Uyghur and other ethnicities who take up temporary residence, typically in Bishkek, to engage in trade. The 1999 Kyrgyzstan census found 46,944 Uyghurs living in the country (1.0%); the 2009 census found 48,543 (0.9%) Unofficial statistics give even higher estimates, ranging from 100,000 to 200,000 people; Uyghur organisations explain the discrepancy as the result of Uyghurs registering themselves as Uzbeks in their official papers.