As you should. I accept the challenge. BSA has the records, they just don't present them to the volunteers at large in an easy way to make comparisons. See below ...
2012 - Overview of Chartered Organizations
The arithmetic I present below is not a perfect presentation. Base upon the data provided, the membership #s are not broken out by program or type unit. So, I just calculated the average # of scouts/unit in the 6 largest denominations and the overall average for all denominations.
Name of Organization Total Units Total Youth #/unit
LDS 37,856 430,557 11.4
UMC 10,868 363,876 33.5
RCC 8,397 273,648 32.6
all Presbyterian 3,597 125,523 34.9
all Lutheran 3,827 116,417 30.4
all Baptist 3,981 108,353 27.2
TOTAL 76,322 1,644,456 21.5
The trend is definitely there. While the LDS have the most # of units, they are definitely smaller than most others.
Thanks for that, very enlightening.