According to the WTS, your baptism never ends until you die even if you DA or are df'd, that is the basis on which they can "reinstate" someone and that person does not need to be rebaptized.
Based on that 37 years; or 32 years minus 5 years of being "inactive."
Blondie ("out" depending on which WT publication you quote)
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w572/15p.114par.4HowJehovah’sWitnessesViewTheirMinistry***If one does not witness, he is not one of Jehovah’s witnesses. To call ourselves witnesses of Jehovah and then to refrain from witnessing, which is ministering, would be taking Jehovah’s name in a vain or worthless way.
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w937/15p.27TenderlyShepherdingJehovah’sPreciousSheep***Inactivity in the ministry or in attending Christian meetings does not mean that the sheep is no longer part of the flock. He remains part of "all the flock" for whom the elders must "render an account" to Jehovah.