Är Boeing 737 ovanligt mottaglig för stressutmattning?

Enligt denna Newsweekartikel - som verkar som en ansedd källa - FAA har utfärdat ett antal luftvärdighetsdirektiv för att ta itu med stressutmattningsbekymmer med 737NG-serien :

Between 2000 and 2011, as the number of NG series in the air grew to more than 2,000, I identified 13 directives that specifically concerned cracking and fatigue issues in the model’s fuselage.

Artikeln fokuserar på potentiella problem med det bakre tryckskottet:

But the most alarming alert concerned involved a repeatedly troubled area called the aft pressure bulkhead (the rear portion of the cabin). In an Airworthiness Directive dated Nov. 5, 2001, the agency called for “immediate corrective action” to deal with a flaw in the aft pressure bulkhead [...] Four airlines had discovered, during checks, that if a 737 made a hard landing, damaging the main landing gear, or simply a certain kind of hard landing that led to shimmying, involving violent swerves on the runway (not uncommon in turbulent weather), the forces transmitted from that impact would end up damaging the aft pressure bulkhead, fatally jeopardizing the tailfin.

There were five alerts about problems with this bulkhead. [Prof. Tony] Ingraffea, after looking at the [details], told me in an email: “Skin cracking and aft bulkhead problems are clearly chronic.” [...] In a written memo to Newsweek, Boeing claimed that to say that there were “persistent problems” with the bulkhead is “not correct” but did not elaborate.

På grund av antalet AD (och andra relevanta uppgifter) är Newsweek noggrann i att 737 är mer mottaglig för stressutmattning än andra liknande flygplan? Är antalet AD för denna fråga ovanlig? Finns det någon mätbar högre risk i samband med att flyga i en 737 på grund av denna fråga?