Oxford vaccine is 70% effective in trials
https://www.bbc.co.uk/news/health-55040635
However the data suggests that by varying dosage levels that might rise to 90% - in the trial, amongst those given 2 high doses protection was 62%, while those who got a low dose then a high dose had 90% protection. 70% seems to be the average for the whole trial and as of right now nobody knows what mechanism is causing better protection by varying dosage.
Anyway the best news for the wider world is that the Oxford vaccine is cheaper and quicker to produce than either of last week’s RNA vaccines and doesn’t need to be stored at ultra low temperatures. So it can easily be deployed anywhere in the world.