Do Medigap Plan Premiums Go Up at a Faster Rate After the Plan Has Been Closed to New Enrollment?

Is there any documented information about Medigap rates going up at a ‘faster rate’ when the plan(s) have been removed from the market when compared to plans that are still active in the market? For example after Plans H, I, and J were closed to new enrollees, have the remaining plan members experienced, on a consistent basis, larger premium increases than the Plans whose membership rate is growing (F, G, K, and N)? I understand individual companies will vary on this point...the question is has there been a 'macro' study to confirm/deny this?
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