Technically just the ones in the relevant period but honestly I would translate all. If the officer can't read the untranslated stamps then he/She can't verify if they fall within the relevant time or not thus you might have to get them translated anyway......
@Rigly68 , couple more questions, in case if you know:
1. Is translation required for visa stamps that have entry and exit dates in English, and also have the country/city names in English, but also have some foreign language words/text as part of the stamp?
2. My passport has notes in my native language that are not visa stamps, but rather observations such as my blood type, the address I was registered in the country I was born, and so on. Do these notes need to be be translated as well?
Thanks in advance.