Colleges and Universities with good CS departments that graduate a lot of undergrads are also a huge factor (quality and quantity). The students in that country

Colleges and Universities with good CS departments that graduate a lot of undergrads are also a huge factor (quality and quantity). The students in that country has the most immediate access, and it is also a big draw of talent from other countries. In 2019 13% of US CS bachelors were awarded to "Nonresident Alien" students, 65% of Masters, and 60% PhD.