In the U.S., the gap is probably better set at 2 million.
There's a big gap in the number of metros just above/just below it:
1,000,000-1,500,000: 16 metros
1,500,000-2,000,000: 4 metros
2,000,000-2,500,000: 11 metros
2,500,000-3,000,000: 7 metros
16 metros from 1 to 1.5 million, but that collapses to 4 in the 1.5 to 2 million range, before picking back up.
Also, 100,000 isn't high sufficiency. 100,000 is a Winchester, VA, which is a small town with extreme D.C. commuters. It's not really a self-sufficient town, just a crazy far exurb, similar to a Kawartha Lakes or Peterborough. I'd say 250,000 should be the cut-off at the bottom.
For the
Capital Region USA:
High Sufficiency= 250k to 750k
- Bristol: 307,614 (most in Tennessee)
- Hagerstown: 293,844 (many in West Virginia)
- Lynchburg: 261,593
- Roanoke: 315,251
- Salisbury: 418,046
Small=750k to 2 million
- Richmond: 1,314,434
- Virginia Beach: 1,799,674
Medium= 2 million to 5 million
Large= 5 million to 10 million
Huge = 10 million+