Ask HN: How much have you saved for retirement?

This blog post says as a Software Engineer working in the US you should have $4 Million in savings to have the same income, in retirement, as a fresh software engineer.

http://chase-seibert.github.io/blog/2014/01/01/saving-for-retirement-as-a-software-engineer.html

How much have you saved for retirement, and at what age?