Not sure Dave, but imaging the training ( may not be that comprehensive?) that would need to be deliver to keep up with that turnover, and the quality issues of always having new people on the line.
Most of the jobs would have only needed about 5 minutes training.
There would have been no site induction apart from being shown the changeroom lunchroom and perhaps the first aid room.
Most of the jobs were simple and repetitive. And had to be done in a short timeframe at each station.
Back then they would have been entry level low skilled jobs with a low wage.
Anyone half smart would have been identified fairly quickly and promoted.
Those with only basic smarts would have stayed on the line doing the menial stuff for as long as they worked there.
7.4% isnt a bad number for sickies.
In the early 80s I had to take the absentee names at the mine I worked at.
Was simple. If their caplamp was still on charge, they werent at work.
We had a 15% average for sickies. One shift was regularly around 20%.
We also had around 5% on compo at any stage.