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).
Numbers about the EA community seem useful for people to know if they have any interest in community building. Examples might include:
(Not listing numbers out of laziness + the hope that someone will create a non-Forum version of this, and get up-to-date numbers at that point.)
These can all be rough estimates, but if someone was off about one of these things by an order of magnitude, I'd think they had some poor models about some aspect of the EA community.
Other random numbers I'll suggest (again, rough estimate):
I want to return to this post at some point, since I feel like my list should be longer. I hope others have better suggestions than mine!
Average yearly donation by EAs (EA survey respondents)