I will give a list of four,I need you to find their common bond, and answer what should be #5 on the list.

1-Kuwait
2-Israel
3-U.A.E
4-Qatar
5-????

1-Sierra Leone
2-Tanzania
3-Ethiopia
4-Somalia
5-?????


1-USA
2-Japan
3-Germany
4-Italy
5-??????


1-Japan
2-S.Korea
3-Russia
4-Taiwan
5-??????

1-Panama
2-Costa-Rica
3-Guatemala
4-Belize
5-?????


1-Luxembourg
2-USA
3-Bermudas
4-San-Marino
5-?????????


1-Chile
2-Argentina
3-Uruguay
4-Venezuela
5-????????

I'll give away ,as an exemple,# 6 on the list.

The common bond is: Richest countries in the world, (according to GDP per capita).

#5 should be Switzerland.