I'm about 35 days out, 6000ly from Sol and have scanned just over 500 systems on my current trip so I guess I'm slower. It always utterly amazes me how far people get so quickly. The guy above you: 8000ly in 4 days? How do you guys do this? Are you just jumping? Guessing your not scanning moons 100,000ls out. My biggest day was travelling 600 ly.
Im of the "if it has clouds scan it" ilk for now. I'm basically taking the quick route for a bit of distance just now till i find a area filled with goodies and take my time. I've managed to bag a fair few EL and terriform worlds by scanning randomly.
Protip: you can find interesting systems by hints in the galaxy map. Look from above and zoom out and slowly zoom back in till you make out small haze marks. Zoom into these on the map and you'll have a system show up. These have been pretty good markers to jump too as all of them have been top money stars, EL, and even main body black holes.