I think you're pretty accurate with your numbers. 10 to 13% is usually what makes us the servant body (elder & m s combined) in the average congregation.
The high Elder to M S ratio was even seen at the K M School that I attended. An Elder who was serving as an attendant at the M S school mentioned that the number of Elders in attendance at his school Friday and Saturday was 180 compared to 115 M Ss. So there is definitely a negative trend developing. It would be interesting to know what the numbers were elsewhere.
The same WT 'heavy' who delivered the talk about higher education spoke on the theme ...'Do All things For God's Glory'. In this talk he hit hard the need for M S s to continue to shun d'fd relatives. Apparently a trend is developing where M S s have been ignoring the GB stance on how they say we should be treating family who are d'fd (ie. 'a simple hello.......yada yada yada').
Anyway the speaker stressed to all in attendance that we could not only consider but to expect that we'll be called in on the carpet over that too! That our privileges could very well be taken away if it comes to light that we are in the slightest way enteracting with d'fd loved ones. That came across as a real threat!
What are the chances that a warning like that will serve to close the gap ratio of Elders to M S s? Not a chance! I know for myself, my first thought after hearing the speaker say that was.....'you can have my gun and badge'.....I'm out of here! I'm sure many a M S in that audience and no doubt nation wide when they hear this same talk will feel the same way.
I would sum up the school as, instead of uplifting the ones who carry their share of the load in the congregation, the M S s got more than their share of a beating. Makes me wonder if the Elders fared any better?