It is pretty self explanatory. After 18+ years it is still running.
Those trolls at the factory probably need some admiration.
So how many ?

LMAO. that is sick. funny but sick

l am thinking one every 2 years should be sufficient. After all, it is been 18 years already with nary a sacrifice. If you over do it, they will see it as brown nosing and may suddenly look down on you with disdain.

funny thing is a Saab is actually the record holder for highest mileage ever on a production vehicle. somthing like 1 million plus miles.

It is not just a question of how many goats to sacrifice, to lead a goat to the slaughter u need a trained judasgoat that will happily lead the way for the others; then tradition demands a scapegoat too, though l find casting an animal into the wilderness to take its chances as the better option to its herdmates that r little more than table fodder.

So there u have it, minimum 3 goats at any one time but only 1 to be slaughtered.

Slaughter as often as u wish to do a goat curry for the local soup kitchen & feed ur local needy.