In the case of there being proportionately more annulments granted in the U. S. — I myself was granted a Declaration of Nullity in my own marriage case.
It was an involved process, albeit a very healing one, for which I am eternally grateful.
I wonder if the reason more annulments are granted in the U. S. is because more are sought in the U. S. by conscientious Catholics who wish to continue to authentically participate in the sacramental life of the Church. I know many who continue to fully participate in the sacraments who are in second and third marriages and have not availed themselves of the annulment process.
I wonder if many more in other cultures are simply “flying under the radar,” fully participating in the sacraments despite divorces and remarriages, and not seeking annulments.