Hmmm. Well if Jolin really did sell 250k+ as has been stated, and DD's share of the sales was 1.92%, m(u) sold around 68k in Taiwan in 2006. Judging from the Jpop chart - m(u) recieved 7.07% compared to Secret's 3.54% of annual sales - Secret sold half of that, or 34k. This is of course based upon the assumption that DD sold 250K, which we're not sure of, but i think those number are decent estimates given the percentages provided by G-Music and the seemingly widespread acceptance of Jolin's sales within Taiwan.

The annual Jpop sales were:

(m)u - 4.4%
Secret - 2.1%

http://www.g-music.com.tw/event/2006_top20/top20_4.html

And according to this this, Dancing Diva sold 210k in Taiwan.

...which would mean (m)u sold 57k and Secret sold 27k in Taiwan for 2006.