Only use these statistics as a guideline, and negotiate the hell out of your compensation, even at a startup. You would be shocked at how much leeway companies have in compensation if they need your skill set. I've worked at preeminent silicon valley companies, middle of the road ones, and startups (been doing this way too long I guess). I've managed to sign for almost 50% over their initial offer a couple of times. The hardest place to negotiate turned out to be the mid-size companies which aren't floating in money like Google, or aren't pissing away money like a startup.

When they ask, "how much are you currently making", just politely say that you would rather not go down that route, and please make me an offer you feel is fair for my skill set, and start from there. Hiring managers and departments do this a lot, and know all the numbers, and you, who change jobs infrequently don't have up to date info. What's shocking is how fast silicon valley salaries are increasing.

When I started this software engineering gig in the mid 1990's, a great offer for a fresh grad out of school was $45,000. Inflation adjusted, that's around $75,000 today. When my small company hires today, I get the special joy of making counter-offers against Facebook and Google, these two companies are simply nuts. Recently lost a fresh grad from a first tier CS school to an offer of $150k annual with $100k starting bonus from Facebook, not to mention RSU. Effectively $350k for the first year for a student with a bachelor of science. It's nuts. This guy was really good, but more realistic offers only lack that starting bonus.