It's hard to find sources measuring weight/volume, but usually goes something like this:
> Extrapolating with the help of estimates from the 2017 National Geographic report that 79% of plastic in landfills ends as free floating waste worldwide (6.3 billion tons), it can be estimated that the U.S. is responsible for 327 billion bags that goes into the seas. And the global contribution to ocean debris is 3.95 trillion bags each year
> Extrapolating with the help of estimates from the 2017 National Geographic report that 79% of plastic in landfills ends as free floating waste worldwide (6.3 billion tons), it can be estimated that the U.S. is responsible for 327 billion bags that goes into the seas. And the global contribution to ocean debris is 3.95 trillion bags each year