Description of the variables

afghanistan

algeria

angola

argentina

australia

austria

bangladesh

belgium

bolivia

botswana

brazil

bulgaria

cameroon

canada

central_africa

chad

chile

china

colombia

congo

czech_republic

denmark

egypt

estonia

ethiopia

finland

france

germany

ghana

greece

greenland

hungary

india

indonesia

iran

iraq

ireland

italy

japan

kazakhstan

kenya

kuwait

kyrgyzstan

lao_pdr

libya

lithuania

madagascar

malaysia

mali

mauritania

mexico

mongolia

morocco

mozambique

myanmar

namibia

netherlands

new_zealand

niger

nigeria

north_korea

norway

pakistan

papua_new_guinea

peru

philippines

poland

portugal

romania

russia

saudi_arabia

slovakia

slovenia

somalia

south_africa

south_korea

spain

sudan

sweden

syria

tanzania

thailand

turkey

uk

ukraine

usa

uzbekistan

venezuela

vietnam

yemen

zambia

zimbabwe