While I understand the reason your asking this, there is a fairly major problem. Namely that the forum keeps track of banned spambots, and the e-mails and Ip addresses they registered with by the user profile. If we actively deleted the profiles of spambots who were banned, they'd be free to register and spam us  again.
Quite apart from the problem that deleting profiles needs to be done manually by moderators, and that would be ----- well quite a task to say the least, particularly sinse it'd be hard to distinguish between spambots and users who just haven't posted in a while, sinse while many spambots do have obvious names like "hot'russian'women45" or whatever, not all do, indeed this is why even if there were some sort of auto delete function that could be installed and run to say remove all users with less than 1 post, I wouldn't recommend using it in case we accidently deleted the profile of a legitimate user.

As to counting number of users, I'm not actually sure if there is a way, particularly sinse there are some long time users who are only occasional visitors and the like, it's a general internet problem.

That isn't fair particularly as some forum users are more active than others.

Well moderation of each new user's post manually would be quite a task, as unfortunately would be any manual checking or   deleting of x thousand users, plus as I said there is the risk of reregistering spambots if we banned their accounts.

Ultimately Tjt, while I do appreciate the desire to get an accurate user number, I'm afraid I'm not exactly sure whether it's worth either the risk of deleting potential human users, or of having spambots reregister, or the huge amount of work and/or custom coding it'd take.

I'm afraid I don't know what you mean by "remove from the user list"

The user list is a list of registered forum users (including banned ones), the only way to remove someone from it would be to delete their account.

I suppose you could have some sort of custom coding filters for the list to say show only users with more than one post in the last x amount of time, though even then your likely to either get some spambots (some spambots post several before they're got rid of), or miss out on some legitimate human users, sinse some people really haven't posted much.

Just as one example in around 2011, I recall a person registered an account representing an orphanage in Vietnam.

She/he was looking for free audio games sinse they had some blind orphans, however she/he didn't actually post a topic, but contacted myself privately. The post count of that user will likely still be zero, but they're definitely a human being not a spambot.

As I said, while I understand your desire to get an accurate user number I'm not really sure if it's worth the huge amount of work and the risk involved.

well tjt, the user list is as I said just a list of all registered accounts, we don't decide who goes on it and who doesn't, the forum generates it automatically and there is no way to remove someone from that list without deleting their account.

It is a problem.

about the best way you could find to determine user numbers would I think be looking at the number of active users in the previous 24 hours. No, this wouldn't show everyone, but it'd at least give an idea of roughly how much activity we had, particularly sinse spambots are less common these days.