I don’t believe this 68 number for a minute. That is a mental retardation classification. Please provide clear scientific studies that prove this data. Not defending Somali’s - this just doesn’t pass the sniff test.
Google “Muslim inbreeding” for a partial answer to your question.
http://www.photius.com/rankings/national_iq_scores_country_ranks.html
I don't believe that number either. Sounds way too high.
Here are two sources.
Your incredulity would be lessened to a great degree if
you had a lot of first hand contact with these people.
There is a reason that they glom onto a barbaric
mind-numbed pseudo religion.
http://www.eutimes.net/2009/11/iq-by-country/
http://www.photius.com/rankings/national_iq_scores_country_ranks.html