Arguably the total number of working H-1B visas (including extensions while waiting for a green card) (and working H-4 dependents) is the more relevant metric.
That number is not tracked directly, but it's about a million or so, all at significantly higher wages than the median US personal income of $31,099/y.
https://qz.com/949589/the-h-1b-visa-cap-tells-you-very-littl...
But regardless, it’s not like all unemployed are competing with body shoppers, while the HN crowd probablybisnt either.
Secondly - H1B can be extended indefinitely while the AOS process is pending, this is in the news right now since Trump's admin announced they are looking into ways to prevent this. The same news are saying over a million H1Bs holders will be affected if the admin succeeds.
The real leeches in this system are the consulting/placement shops.