In JW land, ministers who teach the bible (Publishers) refers to all JW's who go for field service and turn in reports.
While I agree with you on who WT counted as "ministers who teach the bible", I don't necessarily agree that they were all considered as "JWs".
As a born in, 40+ year active "JW", I had always understood, a person wasn't considered to be an actual JW until becoming baptised. My SO confirmed that understanding. Although a person may fully believe and consider themself a JW, living their life as a JW including being active as an unbaptized publisher, they were not considered to be officially a JW but merely an 'associate' until baptism.
Using 'Ministers ...', especially the 'Peak' publisher number to represent JW numbers, seems to be a method to present there is a greater number of JWs than what WT would actually consider internally to be technically true.
Please consider, although you may have understood how things were done when you were an active JW, especially if an Elder, if you have been out of the organization for any length of time, in consideration to all the recent changes within the organization, statistical practices and procedures may have also changed. Since WT is so compartmentalized, those outside of that WT department, will likely not be advised as to changes.
As you may not agree and consider all Ministers as JWs, please explain why "un-baptised publisher" is designated differently than "baptised publisher".