From when the WHO got seriously involved... reliable.
Before that... not reliable. As you say recording deaths but not attributing to coronavirus. Would need to see excess mortality rates for Hubei.
No, they have been v quiet about the actual mortality rates.
There were WHO staff in February I think, but by late January there was intense WHO and media attention on the figures. Before that, it was obvious from their suppression of the doctors warnings that they were trying to cover it up.
There was coverage of a report yesterday suggesting the mortality rate was a lot lower than first thought.
The problem in comparing the China numbers to anywhere else is the measures China put in place to lock down the population. There aren't too many other countries who have mass surveillance & facial recognition to monitor movement of population, or who would like the extent of the controls they put in place.