The Pew report seems to indicate that 2/3rds of "those raised as Jehovah's Witnesses" leave the organization. I wonder what the statistics are for the converts?
I think it is harder for those who converted to leave the organization because they have to admit that they were wrong about religion once again. Some may still be convinced that the Watchtower is doctrinally right in spite of the other faults they find about the organization. Also, it is harder to disconnect when you have "burned your bridges" with old friends and relatives. I think these factors may keep many in the organization.