wow, 17 years is right.
consider that you bought it on October 11th, 27.
RMB 1.788 on October 11, 27, RMB .889 on September 18, 215
RMB 7,, after deducting 1.5% subscription fee, leaves RMB 6,895
RMB 6,895/RMB 1.788 = 6,391.36 copies
6,391.36 copies.