Chronology of OPEC Metrication:

Organization of Petroleum Exporting Countries (OPEC)

145 DZA Algeria

DZA Time Zone +1 Al Jaza’ir (Algeria) (Algiers)
Metric System Adoption: 1843
United Nations Member: 8 Oct 1962

233 VEN Venezuela

VEN Time Zone -4 Venezuela Caracas
Metric System Adoption: 1857 *
Compulsory Metric Implementation: 1912-14
United Nations Member: 15 Nov 1945
Note: International paper size A4 is the established ISO standard adopted by all countries in the world (except the United States and Canada) as well as the official United Nations document format size. Mexico, Costa Rica, Colombia, Venezuela, Chile and the Philippines are places where the US Letter Format is still in common use, despite their official adoption of the ISO standard.
* Metric versus English [Published in 1921] Page 27

238 ECU Ecuador

ECU Time Zone -6, -5 Ecuador Quito
Metric System Adoption: 1865-71
United Nations Member: 21 Dec 1945

88 GAB Gabon

GAB Time Zone +1 Gabon Libreville
Metric System Adoption: 1884-1907
International System Adoption: 1960
United Nations Member: 20 Sep 1960
Member of CEMAC; Currency: Central African CFA Franc (Fr) XAF

81 AGO Angola

AGO Time Zone +1 Angola Luanda
Metric System Adoption: 1905
Compulsory Metric Implementation: 1910
United Nations Member: 1 Dec 1976

143 LBY Libya

LBY Time Zone +2 Libya Tarabulus (Tripoli)
Metric System Introduction: 1913 *
Metric System Adoption: 1927
United Nations Member: 14 Dec 1955
* Italians introduce the metric system into Tripoli in 1913.

107 IRQ Iraq

IRQ Time Zone +3 Iraq (formerly known as Mesopotamia) Baghdad
Metric System Adoption: 1931
International System Adoption: 1960
United Nations Member: 21 Dec 1945
Metric versus English [Published in 1921] Page 32

105 IRN Iran

IRN Time Zone +3.5 Iran Tehran
Metric System Adoption: 1933
Compulsory Metric Implementation: 1935-49
United Nations Member: 24 Oct 1945

108 KWT Kuwait

KWT Time Zone +3 Kuwait Madinat Al Kuwayt (Kuwait City)
International System Adoption: 1961
Compulsory Metric Implementation: 1964
United Nations Member: 14 May 1963

115 ARE United Arab Emirates

ARE Time Zone +4 Al Imarat al Arabiyah al Muttahidah (United Arab Emirates) Abu Dhabi
International System Adoption: 1961
United Nations Member: 9 Dec 1971

112 SAU Saudi Arabia

SAU Time Zone +3 Al Arabiyah as Suudiyah (Saudi Arabia) Riyadh
International System Adoption: 1962
Compulsory Metric Implementation: 1964
United Nations Member: 24 Oct 1945

78 NGA Nigeria

NGA Time Zone +1 Nigeria Abuja
International System Adoption: 1971-73
United Nations Member: 7 Oct 1960
Member of ECOWAS

114 QAT Qatar

QAT Time Zone +3 Qaṭr (Qatar) ‎ad-Dawḥa (Doha)
International System Adoption: 1972
United Nations Member: 21 Sep 1971

Click on the image of Earth here to see when metrication occurred in each country or territory on Earth: