The commodity index of light soda ash was 69.06 on August 29, and fell 0.19 percent than yesterday. Comparing with the peak point of this period 100.00, it drops 30.94 percent. But still rises 0.25 percent than the lowest point 68.89 on July 1st. (Note: the period refers to September 1st, 2012 to now)
Source:
http://www.glassinchina.com/news/newsDisplay_18047.html