[A CA Guy]

They vary. Clerks used to go on ships up and down ladders, but today sit at the computer all day. In the 70'2 my sister's ex made $70,000. If he wanted to cut his scheduel down he would still make $156,000 and if he worked nights, it was possible to make $250,000 perhaps.

Many of those jobs will be automated, so they try to grab the big bucks while they can, but they are no poor.

New folks going in don't make near that money.
That's about all I know.

[A CA Guy]

The above figures are about today and not the 70s. They make mad money.