What's the story with the blue MRTC plaques near the main door on all of the MRTC aircraft?

They say "More Room Throughout Coach" then have two numbers, typically, like 14/115 on an MD80. Does that mean that there are 115 MD80s in the fleet, and this one was the 14th one to be converted?

That's what I assumed, but 5 out of my last 5 flights have been on an MD80 with the 14/115 plaque. What are the odds that these 5 consecutive flights have all been on the same airplane? (consecutive for me, not for the airplane)

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