Google says there are 3,500,000 software engineers in the USA. If they are doing 5,000 a month, that means they are interviewing about 2% of all the engineers in the US each year. That's not totally accurate because it doesn't account for those breaking into the field or if international candidates are going through the process. Either way, that's a lot of candidates.
Define "software engineer"? I know for example the US gov puts basically all tech jobs in the same bucket of IT. Hardcore low-level assembly programmers with people who set up office on business machines.
I would speculate the total number of people the average HN reader would consider a software engineer is much lower.
