http://cnnic.cn/uploadfiles/pdf/2008/7/23/170516.pdf
It is in Chinese.
A few points:
There are totally 14,854,830 domain names, with 80.1% being .cn names.
Among .cn names 63.6% is .cn and 28% is .com.cn.
There are totally around 1,919,000 websites, with 71.4% being .cn, 24.3% .com, and 3.4% .net.
These are just the latest numbers. You can guess the trend.