Chinanews, Beijing, May 31 - Horizon Research conducted a survey among ordinary urbanite families in China, finding that more than 50% of kids aged between 4 and 12 in such families have to attend extra classes, including classes supplementary to school courses and potential development classes. Averagely a family spends about 200 yuan on such classes every month.The survey was conducted in Beijing, Shanghai, Guangzhou, Wuhan, Changsha, Xi'an, Chengdu, and Harbin, covering the adult members of 1,456 families.Actually, nearly 30% of the kids attend more than 1 extra classes every week. Averagely, a kid spends 3.71 hours in such classes every week.The ratio of kids who attend extra classes tends to grow with their age, for more than 61% of the kids between 10 and 12 years old attend extra classes.About 64% of the kids take extra English classes, 25% take painting classes, 18.7% take dance classes, 10.1% learn to play musical instruments, 8.4% take special maths classes, and 5.3% take martial arts classes. There are also classes that are not so "popular", like chess classes and even brain training classes.