Question: In what year did Langfang have a population of 4,358,839 people while Yichun, Heilongjiang have a population of 1,148,126 people?

Related documents: [0]  [DOC] Yichun () is a prefecture-level city on the Songhua river in Heilongjiang province, People's Republic of China. The city is separated from Russia by the Amur River and has an international border of 246 km . At the 2010 census, Yichun has a total population of 1,148,126 while 729,202 people live in 15 districts separated by forests. The greening rate of Yichun is up to 83%. The nickname of Yichun is Lindu (). [END] 
[1]  [DOC] Langfang (), is a prefecture-level city of Hebei Province, which was known as Tianjin Prefecture until 1973. Hebei province was renamed Langfang Prefecture after Tianjin became a municipality and finally upgraded into a prefecture-level city in 1988. Langfang is located approximately midway between Beijing and Tianjin. At the 2010 census, the population of Langfang was 4,358,839, of whom 868,066 lived in the built-up ("or metro") area made of Guangyang and Anci districts; its total area is around 6417.28 km² . Langfang borders Baoding to the southwest, Cangzhou to the south (both prefecture-level cities of Hebei), Beijing to the north and Tianjin to the east. Sanhe City and Dachang Hui County are now conurbated with Beijing, so that they form part of the same built-up area. Langfang is the smallest prefecture-level city of Hebei Province by land area. [END]  
Answer: 2010
2010