To be fair many countries dont want or need them or rely on other allied countries that do have them so they dont have to feild the expense. Other have them but dont officially admit to it. Some cant afford them. But a basic gun type nuclear bomb design like little boy is not technically difficult and could be made by a highschool ap physics class given access to the fissionable material.

That countries don’t want to handle the expense is one of the signs that they haven’t been commoditised.

The number I provided also includes both declared and undeclared nuclear powers.

It’s not just about the ability to make a bomb, it’s about being able to maintain a credible arsenal along with delivery platforms.