F tier - cops, military officers, coast guard, Immigration and custom inspectors
F+ tier - DAs, military, TSA officers
D tier - doctors
D+ tier - psychologists
C tier - nurses
B tier - teachers, private defense attorneys, tax collectors
A tier - social workers, janitors, government agency workers (DMV workers, office jobs, etc), public defenders, pro-bono defense attorneys
S tier - postal workers, firefighters, sanitation workers, veterinarians, anesthesiologists, park employees, forest rangers
Rest in Power p.a.t.c.o, martyrs in the fight for labor rights
EDIT: I'd like to add that this is mostly US-centric. In other countries, doctors probably range from B tier to S tier. As for defense attorneys, I honestly don't know enough about their demographics to determine how many of them are Alan Dershowitz and how many are actual public servants.
yeah how you gonna mention PATCO in the post and not shout out the bus/train driver?