Canada was actually country code 21. We exhausted our available numbers around 2002/2003 and started using 20 after that time.
A good point to note is the US code of 00 and 01. The US used up all their 00 numbers by 1974, at which time they started using 01 for the country code. You can kind of date the NSN by looking at that break. They are now up to the 01-600- range of numbers, so with another war or two, and the new NSNs for new equipment, will use those 01 numbers up eventually, after which I believe they will be using 04.
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