Continuing off of this. The original numbers back at the start were almost definitely under-reported, in part due to lack of diagnosis and in part due to government trying to cover it up before it spread.
However, since it's an international thing now, the numbers are a lot closer to the truth.
It's still likely that it's lower than the actual number, since there are people who avoid the hospital and self-quarantine - due to lack of resources at available hospital, and not wanting to be forcefully quarantined, better to stay home.
There is also how, like the flu or pretty much any other illness, it hits people who already have pre-existing ailments harder (hello elderly and others), so it's more difficult to puzzle out why they exactly died, especially when the hospital staff are already so overworked. Why bother with dead when there are still so many living ones to treat?