German to English Law/Patents Insurance Disability terms

Have read the postings on these, but haven't found one where all three are discussed in comparison to, or in distinction from, one another. I understood "Berufsunfähigkeit" and "Erwerbsunfähigkeit" to mean partial disability and total disability, respectively, but then I read the posting for "Erwerbsminderung," and that meaning seems to be the same as "Erwerbsunfähigkeit" (total or "100%" disability). Are there enough terms in English to distinguish between these three? Each one is defined in a separate paragraph in the contract. I have a feeling "Erwerbsminderung" may be in a slightly different category; would "Reduction in earning capacity/ability" be acceptable for this term? So far I've only seen that translation listed for financial material.