by cheating of course!
just for them points you know
i didn't get panama though?
I think they use US dollar in El Salvador
I think Kosovo and Montenegro should be listed as "none" since they unilaterally adopted Euro (like Ecuador or East Timor did with US Dollar): only Andorra, Monaco, San Marino and Vatican City legally adopted Euro while being outside EU.
I think they should be accepted as the same currency. I was surprised to see Oman and other countries missing in the states, because I didn't imagine that there were spellings other than Riyal.