Question about Xiaomi Smart Band 9

Good morning. I have 2 questions: - How long is the oxygen measurement data stored on the watch and can it be retrieved? For example: can I look up what my oxygen saturation was yesterday at 3 o'clock? - Is the oxygen saturation only available during sleep analysis or just like that? The product description says something about oxygen saturation, but this is not listed in either function of the watch. Unfortunately, these questions are not explained on the manufacturer's website. Thank you very much for your feedback =)