The only source I could find with some concrete figures: http://techcrunch.com/2013/05/18/the-evolution-of-hacker-news/ which is about 2 years old.

- 1.6M views, 200,000 uniques per weekday.

Just from this, I'd guess about 25-50% higher than it was in 2013, but that is just my gut speaking.

So the ask: how would you estimate the number of readers HN has. Even better, what their demographic breakdown is.