Airlines in Africa and the Caribbean are operating the oldest narrowbody aircraft, on average, an Aviation Week fleet analysis shows. And in countries where airlines have at least 100 of the jets in active service, the highest average ages are in Venezuela, Iran and South Africa.

Canada and the U.S. rank just behind those three countries, albeit with a significant gap.

The analysis is based on a fleet database that includes aircraft ages and was calculated only for aircraft delivered and in active service. It does not include new or used aircraft on order.

The average ages could provide some clues as to the best places to find customers for acquiring or leasing aircraft, if sellers and lesser have not found them already. For example, AerCap CEO Aengus Kelly said this month that he does not share concerns about potential overproduction at Boeing and Airbus, in part because some deliveries deferred by financially troubled carriers could be switched to U.S. carriers, where narrowbody fleets are relatively old.

Aviation Week’s analysis shows an average narrowbody age of about 15 years for U.S. carriers, as well as for Canadian airlines, which compares to an average age of about 12 years worldwide. For Venezuela, Iran and South Africa, the average ages are 32.5, 22 and 21.6 years, respectively.

The rankings change a bit when the list is broadened to include countries in which airlines have at least 10 of the jets in service.

That criterion puts the Democratic Republic of the Congo atop the list, with an average age of 37.2 years for its 32 aircraft. Venezuela still ranks second, but the next nine countries with the oldest fleets all have 11 to 30 aircraft with average per-country ages ranging from 22 to 30 years.

Those countries include Republic of Congo (Congo-Brazzaville), Peru, Kyrgyzstan, Angola, Serbia, Pakistan, Afghanistan, Kenya and Sudan.

The youngest narrowbody fleets—starting with the youngest—are in Ireland, Qatar, Hungary, Singapore, Norway and the Philippines, with average ages ranging from 4.4 to 5.9 years.