I can assure you I didn't make them up but you are free to check them yourself.
This is the site I used for the COVID-19 related data: https://ourworldindata.org/coronavirus
Case % - total US cases / total global cases.
Death % - total US deaths / total global deaths
The US population percentage is available from a number of sources but this is the one I used:
https://www.worldometers.info/world-population/
NOTE: I chose the COVID data source partly because it's easy to use for this sort of thing but mostly because their data management standards are well documented and properly structured. Since I work in Data Mgt. in IT at a major corporation, I am very familiar with what constitutes "proper" and therefore did not want to use any data source that I did not validate as trustworthy.
Caption this Meme
