TL;DR: the better your score, the better your chances.
I'm going to speak in generalities, as there are exceptions to every rule. So this is generally how ranking works with respect to exam results; YMMV.
Qualifying veterans new to state service get an automatic rank of 1 as long as they simply pass the exam. Once they're hired, they lose this privilege for future exams.
If you're new to state service and you're competing against someone who is already in state service, they may get three service credits which are applied to their score.
Therefore, it's possible for you both to get a 95%, but with the three service credits your current state worker gets a 98%. Which now makes them and anyone else in their position rank 1, along with veterans, and you're now rank 2, even though you have a 95%.
This is true for all scores/ranks. You could get 85%, but someone with state service gets service credit along with their 85%, so they now have 88%, you still have 85%, and now you've dropped a rank.
So... using the examples above, the scores and rankings could end up looking something like this:
Rank 1: 98%
Rank 2: 95%
Rank 3: 90%
Rank 4: 88%
Rank 5: 85%
Rank 6: 80%
It's not always a hard and fast six limited 70-75-80-85-90-95 scoring or ranking system. Yes, 70% is passing. But your chances of being called for an interview, especially in a competitive class, are pretty slim if you're not hitting at least 90%, as demonstrated above. You're not even on the radar.