1. This is by GDP per capita, not GDP. 2. There are several other quizzes on this topic already. 3. Monaco and Liechtenstien aren't recognized by the UN?
Looks like you're using the IMF data on Wikipedia which for some reason doesn't include those two..
You could use the data from the United Nations instead if you're going to cite them as criteria for inclusion on the list. The UN list is more inclusive.
My answer to number 1 is that I have changed the quiz accordingly, sorry about that. Number 2, this was only my second quiz and I was trying to 'play it safe'. Number 3, as you have correctly identified that is my current resource material and I will look in to UN website in future to compare. Thankyou for the feedback.
You could use the data from the United Nations instead if you're going to cite them as criteria for inclusion on the list. The UN list is more inclusive.