You've reminded me I should donate again, its been a while... though one small correction, O- is not the most common at all. It makes up under ~10% of the population as a rule: https://www.healthdirect.gov.au/blood-types
If you're super curious Google transport later security (TLS), the modern incarnation. Used practically everywhere on the internet, whether users realize it or not 😀
You've reminded me I should donate again, its been a while... though one small correction, O- is not the most common at all. It makes up under ~10% of the population as a rule: https://www.healthdirect.gov.au/blood-types