It does depend how you use it. If it spends a lot of time with the screen on then that percentage will be high (and a new phone is likely to spend a lot of time with the screen on). If it spends most of the day in your pocket the percentage will be lower. And if the screen on time is spent doing something cpu intensive the screen percentage will appear lower as the cpu is using more power, etc.
See how the battery like works, and worry about the percentage if the overall life is a problem, not otherwise. As it's AMOLED use dark backgrounds and wallpapers where possible if you want to reduce power usage (AMOLED is very efficient when displaying black, as it just turns the LEDs off).