Large raises aren’t unusual early in a career, especially if they come with a promotion in title or responsibility. Double-digit raises (10% or more) are typically considered promotions unless there’s some weird demographic stuff going on that drives the salary of your career field up – everyone I know who’s gotten a double-digit raise has been told that it comes with increased responsibility.
An 8% raise says to me “you have been kicking ass and taking names, we owe our survival/profitability as a business to you in some way, and please understand that we appreciate what you do.” Businesses don’t give out raises like that unless you have earned them.
The US military, on the other hand, gives out raises like candy. In the military a newly commissioned officer makes just under $30,000/yr, and gets no raise his first year unless Congress approves a cost-of-living raise, typically ~2%. At the end of his second year, however, he gets both a rank increase and longevity increase, totaling about 28%, bumping him up to about $37,000. The next year he gets a longevity increase of 15%, and the following year a rank increase and a longevity increase of another 17%. That’s a 77% increase over starting pay in four years, which is basically unheard-of. Later longevity increases tend to be more modest, and the next rank increase isn’t until the 8-10 year mark… but it’s another 20%+ raise.
So 8% is pretty damned good, especially if you get it early on, because then every 5% and 3% raise thereafter is going to be 8% larger than it would have been.