When merging populations into the dataset, these countries don't have mean populations:
Bahamas
Bolivia (Plurinational State of)
Cape Verde
Congo
Congo (Democratic Republic of the)
Côte d'Ivoire
Egypt
Gambia
Hong Kong, China (SAR)
Iran (Islamic Republic of)
Korea (Republic of)
Kyrgyzstan
Lao People's Democratic Republic
Micronesia (Federated States of)
Moldova (Republic of)
Palestine, State of
Saint Kitts and Nevis
Saint Lucia
Saint Vincent and the Grenadines
Slovakia
Tanzania (United Republic of)
The former Yugoslav Republic of Macedonia
Venezuela (Bolivarian Republic of)
Viet Nam
Yemen
When merging populations into the dataset, these countries don't have mean populations: Bahamas Bolivia (Plurinational State of) Cape Verde Congo Congo (Democratic Republic of the) Côte d'Ivoire Egypt Gambia Hong Kong, China (SAR) Iran (Islamic Republic of) Korea (Republic of) Kyrgyzstan Lao People's Democratic Republic Micronesia (Federated States of) Moldova (Republic of) Palestine, State of Saint Kitts and Nevis Saint Lucia Saint Vincent and the Grenadines Slovakia Tanzania (United Republic of) The former Yugoslav Republic of Macedonia Venezuela (Bolivarian Republic of) Viet Nam Yemen