I probably should have explained why some of the data from before 2006/7 might be an undercount. More information can be found in the link below, but the key point is that CTCs and academies did not return information on permanent exclusions until 2000/01. There are even bigger problems for suspension data, which doesn't affect what I am looking at, but does mean that the DfE has a reason to start their data after those issues were resolved. https://assets.publishing.service.gov.uk/media/5a7c546ded915d338141e190/sfr22-2010.pdf
I probably should have explained why some of the data from before 2006/7 might be an undercount. More information can be found in the link below, but the key point is that CTCs and academies did not return information on permanent exclusions until 2000/01. There are even bigger problems for suspension data, which doesn't affect what I am looking at, but does mean that the DfE has a reason to start their data after those issues were resolved. https://assets.publishing.service.gov.uk/media/5a7c546ded915d338141e190/sfr22-2010.pdf