I think it might be interesting and valuable to create a "list of numbers every EA should know", in a similar vein to Latency Numbers Every Programmer Should Know and Key Numbers for Cell Biologists.
I was originally thinking of either a) making the whole list myself, or b) convincing someone else (eg, an RP intern) to do it, but on AaronGertler's advice I decided to turn to the Forum to help with crowdsourcing this problem.
We can use upvotes/downvotes and comments to debate which numbers should be worth including/excluding.
So what are some key numbers that (almost) every EA should know?
Feel free to answer with either important numbers that you think are cause-specific (eg, numbers of chickens currently alive in factory farms, Toby Ord's x-risk estimates, extreme poverty rates in 1950 vs 2018) or relatively cause agnostic (eg, $billions that Open Phil has, expected lifespan of social movements, number of atoms in the observable universe).
FINAL UPDATE: The deck is now published.
This is amazing. I'd be happy to create an Anki deck for these and any other numbers suggested in this thread.
EDIT: Judging from the upvotes, there seems to be considerable interest in this. I will wait a few days until people stop posting answers and will then begin creating the deck. I'll probably use the CrowdAnki extension to allow for collaboration and updating; see the ultimate-geography GitHub repository for an example.
You can embed flashcard decks into LW and EA Forum posts:
So you could consider creating one of those.