| Year | Provinces |
| 2010 | Beijing, Tianjin, Hebei, Shandong, Henan, Anhui, Jiangsu, Shanghai, Hubei |
| 2012 | Beijing, Tianjin, Hebei, Shandong, Henan, Anhui, Jiangsu, Shanghai |
| 2014 | Beijing, Tianjin, Hebei, Shandong, Henan, Anhui, Jiangsu, Shanghai |
| 2016 | Beijing, Tianjin, Hebei, Shandong, Henan, Anhui, Jiangsu, Shanghai |