Ask HN: A lot less traffic from China logged by Google Analytics

I just noticed that after two years of having China as a Top 3 country in Google Analytics, since October it started to decline sharply and now is in place 48 out of the 107 countries we get traffic from.

Traffic volume from China reported by Google Analytics seems to be now 10-20 times less than it used to be.

However, I am positive that Chinese users are still there. For example, we get a 15-20% drop in application usage during Chinese New Year's break time.

Why do I have this effect in Google Analytics?

Are Chinese web visitors using Tor or blocking Javascript Google Analytics code?