For existing employees, this is rather high, but as you did, you should discount this. To get that boost with your current employer, you need to (i) be irreplaceable for a critical service; or (ii) show proof of external offers.
HR/Finance will sets wages at low-mid market so that the 10 other high performing/underpaid employees in your situation will stay and only you will leave. HR's fine with that bet, and people with initiative like you are the victors.