美国每年有五万新博士, 两万多新MD。

https://www.forbes.com/sites/michaeltnietzel/2024/02/05/number-of-doctoral-degrees-awarded-in-us-rebounds-to-all-time-high/#:~:text=The%20number%20of%20research%20doctorates,relatively%20complete%20data%20are%20available.