This chart is often shown and as far as I can tell quite accurate; however, there are lies, the truth, and statistics.
The values not shown on this chart are critically important to understanding chart: Percent of population under 18yrs AND membership headcount as a percentage of total elgible youth.
Scouting America has held steady at 2% of total elgible youth until about 3 years ago. Specifically retention has increasingly gone down. The organization knows how to recruit but units dont know how to retain.