Depends on the pickups. Your average pickups might have like 20% influence, hotter pickups (like EMG) might have up to like 80%, and if you have something like really crappy brand-x active pickups it might be closer to the full three digits. I personally prefer very transparant pickups for the neck, but I'm sad to say I've never found one I really like. All those percentages are rough guesses, btw. Different people also have different degrees of influence. Some people sound the same through pretty much all pickups, and some people almost exaggerate tonal differences and subtleties when they play (which can be very good).