What countries use kuna?

I'm curious to know, which countries currently utilize the kuna as their official currency? I understand that kuna is the monetary unit of some nations, but I'm not entirely sure which ones specifically. Is kuna used widely across multiple countries, or is it more concentrated in a particular region? Are there any plans for other nations to adopt kuna in the future, or is its use primarily limited to its current adopters? It would be great to gain a clearer understanding of the global reach and influence of the kuna.