The information you have requested is not currently published by the department. The department has written to the UKSA with regard to this matter. Please see the link below: https://www.statisticsauthority.gov.uk/correspondence/response-from-daniel-shaw-to-ed-humpherson-parliamentary-question-response/.
In the Chief Statistician’s response to the UKSA, we committed to investigate whether there is data held by the Department which can inform understanding of the effect of the NRPF condition. Following our investigation, we have now published information relating to change of conditions at: https://www.gov.uk/government/publications/immigration-protection-data-august-2020
Migrants coming to the UK are expected to maintain and support themselves and their families without posing a burden on the UK’s welfare system. Access to benefits and other publicly funded services reflects the strength of a migrant’s connections to the UK.
The Home Office publish a range of statistics on entry clearance visas, and extensions of leave in the UK in the quarterly Immigration Statistics. However, these do not show the number of people subject to NRPF.