Narrow gauge around the world - where was it most common?

Having recently become interested in narrow gauge Garratt locomotives, I am curious about which parts of the world was narrow gauge more common?

Did narrow gauge last much longer in other parts of the world than the narrow gauge movement in the United States?

I am aware that what would have been narrow gauge in the United States was in some countries "standard gauge," for example 3 ft. 6 in. was the "standard gauge" in some nations.

Lack of economic growth may have played a role in some narrow gauges surviving - but simple persistence may have played a role as well.

The Rio Grande hauled freight on the San Juan extension until 1968. The White Pass hauled freight until 1982. There are still a few industrial narrow gauge operations such as U.S. Gypsum.

How did the rest of the world compare to the United States? Was the percentage of narrow gauge railroads, out of the total mileage of track in service, higher, lower, or about the same as teh U.S?