I am looking for statistics (with sources) relevant to the following:
to what degree do Chinese internet users access content hosted within
Mainland China, as compared to content physically hosted in a foreign
country?

At some stage I came across a study that suggested 72% of Chinese
internet traffic remains domestic, but I have lost the source.

Hi,

Wasn't easy, however I found a bit of info at
http://www.cctec.com/maillists/nanog/historical/0209/msg00785.html
talking about 90% of traffic staying domestic.

Every search turned up majority with censorship bans, stopping users
from searching outside of china. This has now been lifted, however
givernment is monitoring searchs as stated here:
http://www.heritage.org/Research/AsiaandthePacific/bg1806.cfm

It's all amazing stuff, I'd imagine people are too scared to search
outside of china, secondly most sites are hosted in china are
chineese, so they would keep it local for that reason too.

Barry

Solid information to answer your question does not exist, as far as I
know and would be very hard to get. From interviews I have conducted
with internet users in China, I conclude that most people are not
interested in what is happening in the outside world. That would not
be very different from the US, where most traffic would also be
domestic.

www.chinaherald.net/connecting