is ISO-2022-CN actually used?

[Markus Scherer]

Question: Is the ISO-2022-CN or ISO-2022-CN-EXT charset for Chinese actually used significantly?

I am aware that there is a significant user base for ISO-2022-JP and its subvariants (for Japanese).

I am aware that there are numerous implementations of ISO-2022-CN converters.

However, I would like to know if ISO-2022-CN is actually used, or if Chinese users and 
their
software rather use other charsets like GB 2312, GBK, GB 18030, Big 5, EUC-CN, EUC-TW, 
HZ.
Do you have anecdotal evidence from what Chinese versions and competitors of Hotmail, 
AOL, etc. do
for email/SMTP charsets for Chinese?
Do you know of any source of statistics for this kind of question?

Thank you very much,
markus