Why are millions of apartments in China sitting empty? How has the country managed to produce as much cement in two years as the US did in the last century? For a special edition celebrating the Lunar New Year, the BBC's Asia Pacific editor Celia Hatton looks at the significance of eight numbers representing different aspects of modern China. Celia teams up with some of the BBC's China correspondents and analysts to look at topics ranging from China's marriage rates to its zodiac calendar.