The NCA said suspects include doctors, teachers, Scout leaders, care workers and former police officers. In total, only 39 registered sex offenders are among those arrested.
Officers have searched 833 properties and examined 9,172 computers, phones and hard drives.
The NCA said it built up "intelligence packages" on suspects and sent them to police forces across Britain.
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Doug Bergeson, from Wisconsin, USA, calmly drove himself to hospital and walked into the emergency room to ask for help.
The venue will open its doors again for the first time since May's bombing on September 9 for the We Are Manchester concert .
Reports peaked in June, when the London Bridge and Finsbury Park attacks took place, with the service receiving 5,703 calls.