8,000 Dissenter martyrs revisited

Is this 8,000 martyrs an inflated figure for the Stuart persecution? Michael Watts in his magisterial first volume of his multi-volume work The Dissenters (Clarendon Press 1978), reckons that W.C. Braithwaite was correct when he stated that 15,000 Quakers alone suffered during this era by "fines, imprisonment, and transportation" into exile and 450 died in prison (p.236). I just glanced at Gerald R. Cragg's Puritanism in the Period of the Great Persecution, another great book on this era, but could see nothing where he gave statistics of those who died in prison.

If 450 Quakers died in prison, that would mean there were 7,500 other Dissenters from the Presbyterian, Congregationalist and Baptist ranks that perished in the prisons--and that seems unlikely to me as the Quakers suffered very heavily in this era.

Does anyone have any other statistics?