Our case took around 14 months for the EB-1 from the first call to lawyer to the green card in our mailbox.
How long including citizenship, if that was the goal?
Does this timeline depend on country of birth?
Yes, you'll want to google for the "Visa Bulletin" to see the current dates for different countries. India and China are currently backlogged.
Indians applying for EB-2 have a waiting time of 200 years based of the total number of available visas per year and pending cases.
I became a citizen without an attorney and from start to finish it was about 5 years... Different process used though (got married).
Got a pile of paper about 2 inch high from all the forms I had to fill, mail that I sent and received, etc... Painful process.