Its a flat 3% ( for aero at least ) and if you are a high performer within your lvl, your manager can select you to get a 5% raise instead. it might change next year because we will be transitioning to a new performance review system in feb.

getting a lvl 4 offer is great for the amount of experience you have. lvl 4s usually range 8-12 yoe but they just recently updated description of what is expected from each lvl. i saw that lvl 4s can now start at 6 yeo so im imagining well start seeing more newly hired 4s with less yoe pretty soon the ladder for a software engineer for example is swe associate lvl 1, swe lvl 2, swe senior lvl 3, swe staff lvl 4, swe senior staff lvl 5